Dengue
Diagnosis, Diagnostics, Immunodiagnosis
& Immunodiagnostics:
3183. Chaturvedi UC.
Elbishbishi EA. Agarwal R. Mustafa AS. Cytotoxic factor-autoantibodies:
possible role in the pathogenesis of dengue haemorrhagic fever. FEMS Immunology & Medical
Microbiology. 30(3):181-6, 2001 Apr.
Abstract
During dengue virus infection a unique cytokine, cytotoxic factor (hCF),
is produced that is pathogenesis-related and plays a key role in the
development of dengue haemorrhagic fever (DHF). However, what regulates the
adverse effects of hCF is not known. We have previously shown that anti-hCF
antibodies raised in mice, neutralise the pathogenic effects of hCF. In this
study we have investigated the presence and levels of hCF-autoantibodies in
sera of patients with various severity of dengue illness (n=136) and normal
healthy controls (n=50). The highest levels of hCF-autoantibodies
(mean+/-S.D.=36+/-20 U ml(-1)) were seen in patients with mild illness, the
dengue fever (DF), and 48 out of 50 (96%) of the sera were positive. On the
other hand the hCF-autoantibody levels declined sharply with the development of
DHF and the levels were lowest in patients with DHF grade IV (mean+/-S.D.=5+/-2
U ml(-1); P=<0.001 as compared to DF). Only one of the 13 DHF grade IV
patients had an antibody level above the 'cut-off' value (mean plus 3 S.D. of
the control sera). The analysis of data with respect to different days of
illness further showed that the highest levels of hCF-autoantibodies were
present in DF patients at >9 days of illness. Moreover, the DF patients at
all time points, i.e. 1-4, 5-8 and >9 days of illness had significantly
higher levels of hCF-autoantibodies (P<0.001) than patients with DHF grade
I, II, III and IV. In addition DHF grade I and grade II patients had
significantly more positive specimens than DHF grade III and grade IV patients
at all time points. These results suggest that elevated levels of
hCF-autoantibodies protect the patients against the development of severe forms
of DHF and, therefore, it may be useful as a prognostic indicator.
3184. Cohen J.
'Breeding' antigens for new vaccines. Science. 293(5528):236-8, 2001 Jul 13.
3185. Gagnon SJ.
Leporati A. Green S. Kalayanarooj S. Vaughn DW. Stephens HA.
Suntayakorn S. Kurane I. Ennis FA.
Rothman AL. T cell receptor Vbeta gene usage in Thai children with
dengue virus infection.American Journal of Tropical Medicine &
Hygiene. 64(1-2):41-8, 2001 Jan-Feb.
Abstract
T lymphocyte activation during dengue is thought to contribute to the pathogenesis
of dengue hemorrhagic fever (DHF). We examined the T cell receptor Vbeta gene
usage by a reverse transcriptase-polymerase chain reaction assay during
infection and after recovery in 13 children with DHF and 13 children with
dengue fever (DF). There was no deletion of specific Vbeta gene families. We
detected significant expansions in usage of single Vbeta families in six
subjects with DHF and three subjects with DF over the course of infection, but
these did not show an association with clinical diagnosis, viral serotype, or
HLA alleles. Differences in Vbeta gene usage between subjects with DHF and
subjects with DF were of borderline significance. These data suggest that the
differences in T cell activation in DHF and DF are quantitative rather than
qualitative and that T cells are activated by conventional antigen(s) and not a
viral superantigen.
3186. Juffrie M.
Meer GM. Hack CE. Haasnoot K.
Sutaryo. Veerman AJ. Thijs LG. Inflammatory mediators in dengue
virus infection in children: interleukin-6 and its relation to C-reactive
protein and secretory phospholipase A2. American Journal of Tropical Medicine
& Hygiene. 65(1):70-5, 2001 Jul.
Abstract
To assess
the potential role of interleukin-6 (IL-6) in the pathogenesis of dengue virus
infection, levels of this cytokine were measured in children with dengue virus
infection on admission to the hospital. As presumed surrogate markers of IL-6,
C-reactive protein (CRP) and secretory phospholipase A2 (sPLA2) were measured.
Three groups were studied: 33 apparently healthy children as negative controls,
11 children with bacterial infections as positive controls, and 186 children
with serologically documented dengue virus infection. One-hundred and fifteen
patients had dengue fever (DF) and 71 had dengue hemorrhagic fever (DHF).
Compared with healthy controls, dengue shock syndrome (DSS) patients had
significantly higher levels of IL-6 on admission (P < 0.05), comparable with
those in positive controls. Dengue patients with shock had significantly higher
levels of IL-6 than normotensive patients (P < 0.001) and higher levels of
IL-6 were associated with a higher incidence of ascites. C-reactive protein
concentrations in dengue patients and in healthy children were not different,
but lower than in children with bacterial infections (P = 0.008). Secretory
phospholipase A2 levels were higher in dengue patients than in apparently
healthy children (P < or = 0.05) and similar to those in children with
bacterial infection. Dengue shock syndrome patients had significantly higher
sPLA2 concentrations than normotensive patients (P = 0.02). These data indicate
that IL-6 and sPLA2 may have a pathogenetic role only in the most severe forms
of dengue virus infection.
3187. Kanesa-thasan N.
Sun W. Kim-Ahn G. Van Albert S. Putnak JR. King A. Raengsakulsrach B. Christ-Schmidt H. Gilson
K. Zahradnik JM. Vaughn DW.
Innis BL. Saluzzo JF. Hoke CH Jr. Safety and immunogenicity of
attenuated dengue virus vaccines (Aventis Pasteur) in human volunteers.
Vaccine. 19(23-24):3179-88, 2001 Apr
30.
Abstract
A randomized, controlled, double-blinded study was conducted to determine safety and immunogenicity of five live attenuated dengue vaccines produced by Aventis Pasteur (AvP). The study was completed with 40 flavivirus non-immune volunteers: five recipients of each monovalent (dengue-1, dengue-2, dengue-3, or dengue-4) vaccine, ten recipients of tetravalent (dengue-1, dengue-2, dengue-3, and dengue-4) vaccine, and ten recipients of vaccine vehicle alone. All vaccines were administered in a single subcutaneous dose (range, 3.6-4.4 log(10) plaque forming units). No serious adverse reactions occurred in volunteers followed for 6 months after vaccination. Five vaccine recipients developed fever (T > or = 38.0 degrees C), including four tetravalent vaccinees between days 8 and 10 after vaccination. Dengue-1, dengue-2, dengue-3, or dengue-4 vaccine recipients reported similar frequency of mild symptoms of headache, malaise, and eye pain. Tetravalent vaccinees noted more moderate symptoms with onset from study days 8-11 and developed maculopapular rashes distributed over trunk and extremities. Transient neutropenia (white blood cells < 4000/mm3) was noted after vaccination but not thrombocytopenia (platelets < 100,000/mm3). All dengue-3, dengue-4, and tetravalent vaccine recipients were viremic between days 7 and 12 but viremia was rarely detected in dengue-1 or dengue-2 vaccinees. All dengue-2, dengue-3, and dengue-4, and 60% of dengue-1 vaccine recipients developed neutralizing and/or immunoglobulin M antibodies. All tetravalent vaccine recipients were viremic with dengue-3 virus and developed neutralizing antibodies to dengue-3 virus. Seven volunteers also had multivalent antibody responses, yet the highest antibody titers were against dengue-3 virus. The AvP live attenuated dengue virus vaccines are safe and tolerable in humans. The live attenuated tetravalent dengue vaccine was most reactogenic, and preferential replication of dengue-3 virus may have affected its infectivity and immunogenicity.
3188. Lok SM. Ng ML. Aaskov J. Amino acid and phenotypic changes
in dengue 2 virus associated with escape from neutralisation by IgM
antibody.Journal of Medical Virology.
65(2):315-23, 2001 Oct.
Abstract
Two dengue 2-specific IgM monoclonal antibodies (MAb) recognised spatially unrelated epitopes on the envelope (E) protein of dengue 2 virus, which were also recognised by serum from 20 and 50%, respectively, of patients with a primary dengue 2 infection. Dengue 2 virus populations escaping neutralisation by MAb 6B2 (representing the majority population of dengue 2-specific IgM MAbs ) had a deduced amino acid change (G-S) in the pre-Membrane (prM) protein at position 15 and a second in the E protein at E311 (E-G). The change in the E protein was adjacent to the only other epitopes on dengue 2 virus (E307, E383-385) involved in neutralisation that have been identified but that were recognised by IgG antibodies. Dengue 2 virus escaping neutralisation by IgM MAb 10F2, representing the minority population of dengue 2-specific IgM MAbs, had the same deduced amino acid change (G-S) at prM15 as the 6B2 neutralisation escape mutant dengue 2 virus population and four deduced amino acid changes in the E protein (E69, T-I, in the glycosylation motif; E71, E-D; E112, S-G; E124, I-N), which may be close enough to each other to form a single epitope and a fifth at E402 (F-L) in a region of the E protein of TBE virus essential for the low pH-induced E protein dimer-trimer transition. The 10F2 neutralisation escape mutant, but not the 6B2 one, had lost its ability to cause fusion from within Aedes albopictus mosquito cells and was inactivated more rapidly than the 6B2 neutralisation escape mutant and wild type viruses at 42 degrees C. Dengue 2 viruses passaged in BHK cells in the absence of a selecting antibody, shared a common amino acid (S) at E53, which differed from both wild type and neutralisation escape mutant virus populations at this position (P) and may have been responsible for a significant reduction in the ability of these "passage control" virus populations to be neutralised by both 6B2 and 10F2 antibodies. Copyright 2001 Wiley-Liss, Inc.
3189. Mustafa AS. Elbishbishi EA. Agarwal R.
Chaturvedi UC. Elevated levels of interleukin-13 and IL-18 in patients
with dengue hemorrhagic fever.FEMS Immunology & Medical Microbiology. 30(3):229-33, 2001 Apr.
Abstract
Interleukin (IL)-13 is produced by T helper 2
(Th2)-type cells and inhibits the production of proinflammatory cytokines by
activated monocytes, while IL-18 is a pleiotropic cytokine that induces
interferon-gamma and plays an important role in the development of Th1-type
cells. Role of the shift from a Th1-type response to Th2-type has been
suggested in the pathogenesis of dengue hemorrhagic fever (DHF). This study was
undertaken to investigate the possible protective/pathogenic role of IL-13 and
IL-18 in patients with DHF. Sera were collected from a total of 84 patients
with various grades of dengue illness and 21 normal healthy controls and tested
for IL-13 and IL-18 levels using commercial enzyme-linked immunosorbent assay
kits. The results showed that very low levels of IL-13 (4+/-3 pg ml(-1)) and
IL-18 (15+/-4 pg ml(-1)) were detected in the sera of healthy controls. In
dengue patients, the levels of IL-13 and IL-18 were the highest in the patients
with DHF grade IV (205+/-103 pg ml(-1) and 366+/-155 pg ml(-1), respectively)
and the lowest in patients with dengue fever (22+/-12 pg ml(-1) and 76+/-50 pg
ml(-1), respectively). Both the cytokines appeared (IL-13=20+/-11 pg ml(-1) and
IL-18=70+/-45 pg ml(-1)) during the first 4 days of illness and reached peak
levels (IL-13=204+/-96 pg ml(-1) and IL-18=360+/-148 pg ml(-1)) by day 9
onwards. The presence of high levels of IL-13 and IL-18 during severe illness
and late phases of the disease suggests that both of these cytokines may
contribute to the shift from a Th1- to Th2-type response and thus to the
pathogenesis of DHF.
3190. Saeed MF.
Nunes M. Vasconcelos PF. Travassos Da Rosa AP. Watts DM.
Russell K. Shope RE. Tesh RB.
Barrett AD. Diagnosis of Oropouche virus infection using a recombinant
nucleocapsid protein-based enzyme immunoassay. Journal of Clinical
Microbiology. 39(7):2445-52, 2001 Jul.
Abstract
Oropouche
(ORO) virus is an emerging infectious agent that has caused numerous outbreaks
of an acute febrile (dengue-like) illness among humans in Brazil, Peru, and
Panama. Diagnosis of ORO virus infection is based mainly on serology. Two
different antigens, hamster serum antigen (HSA) and Vero cell lysate antigen
(VCLA), are currently used in enzyme immunoassays (EIAs) in Brazil and Peru,
respectively, to investigate the epidemiology of ORO virus infection. Both
antigens involve use of infectious virus, and for this reason their use is restricted.
Consequently, the frequency and distribution of ORO virus infection are largely
unexplored in other countries of South America. This report describes the use
of a bacterially expressed recombinant nucleocapsid (rN) protein of ORO virus
in EIAs for the diagnosis of ORO virus infection. The data revealed that the
purified rN protein is comparable to the authentic viral N protein in its
antigenic characteristics and is highly sensitive and specific in EIAs. Among
183 serum samples tested, a high degree of concordance was found between rN
protein-based EIA and HSA- and VCLA-based EIAs for the detection of both ORO
virus-specific immunoglobulin M (IgM) and IgG antibodies. The high sensitivity,
specificity, and safety of the rN protein-based EIA make it a useful diagnostic
technique that can be widely used to detect ORO virus infection in South
America.
3191. Sullivan NJ.
Antibody-mediated enhancement of viral disease. [Review] [128 refs]
Current Topics in Microbiology & Immunology. 260:145-69, 2001.
3192. Tolou HJ.
Couissinier-Paris P. Durand
JP. Mercier V. de Pina JJ.
de Micco P. Billoir F. Charrel RN.
de Lamballerie X. Evidence for recombination in natural populations of
dengue virus type 1 based on the analysis of complete genome sequences. Journal
of General Virology. 82(Pt 6):1283-90,
2001 Jun.
Abstract
Recombination events are known to occur in non-segmented RNA
viruses like polioviruses or alphaviruses. Analysis of the subgenomic sequences
of dengue virus type 1 (DENV-1) structural genes has recently allowed the
identification of possible recombination breakpoints. Because DENV is a major
human pathogen, this discovery might have important implications for virus
pathogenicity, vaccine safety and efficiency, or diagnosis and, therefore, requires
clear confirmation. We report the complete sequence determination of one Asian
and two African strains of DENV-1 isolated from human patients. Rigorous
sequence analysis provided strong evidence for the occurrence of intragenomic
recombination events between DENV-1 strains belonging to different lineages.
Singapore S275/90 strain appears to be the evolutionary product of a
recombination event between viruses belonging to two distinct lineages: one
lineage includes an African strain isolated in Abidjan (Ivory Coast) and the
other includes isolates from Djibouti and Cambodia. The 'Recombination
Detection Program', bootscanning and analysis of diversity plots provided
congruent results concerning the existence of a two-switch recombination event
and the localization of recombination breakpoints. Thus, the 5' and 3' genomic
ends of the Singapore S275/90 strain were inherited from a Djibouti/Cambodia
lineage ancestor and an internal fragment located in the envelope/NS1 region
originated from an Abidjan lineage ancestor.
3193. Vasconcelos PF.
Luna EJ. Galler R. Silva LJ.
Coimbra TL. Barros VL. Monath TP.
Rodigues SG. Laval C. Costa ZG.
Vilela MF. Santos CL. Papaiordanou CM. Alves VA. Andrade LD. Sato HK.
Rosa ES. Froguas GB. Lacava E.
Almeida LM. Cruz AC. Rocco IM.
Santos RT. Oliva OF. Brazilian Yellow Fever Vaccine Evaluation
Group. Serious adverse events associated with yellow fever 17DD vaccine in
Brazil: a report of two cases. [see comments]. Lancet. 358(9276):91-7, 2001 Jul 14.
Abstract
BACKGROUND: The yellow fever vaccine is regarded as one of the
safest attenuated virus vaccines, with few side-effects or adverse events. We
report the occurrence of two fatal cases of haemorrhagic fever associated with
yellow fever 17DD substrain vaccine in Brazil. METHODS: We obtained
epidemiological, serological, virological, pathological, immunocytochemical,
and molecular biological data on the two cases to determine the cause of the
illnesses. FINDINGS: The first case, in a 5-year-old white girl, was
characterised by sudden onset of fever accompanied by headache, malaise, and
vomiting 3 days after receiving yellow fever and measles-mumps-rubella
vaccines. Afterwards she decompensated with icterus and haemorrhagic signs and
died after a 5-day illness. The second patient-a 22-year-old black
woman-developed a sore throat and fever accompanied by headache, myalgia,
nausea, and vomiting 4 days after yellow fever vaccination. She then developed
icterus, renal failure, and haemorrhagic diathesis, and died after 6 days of
illness. Yellow fever virus was recovered in suckling mice and C6/36 cells from
blood in both cases, as well as from fragments of liver, spleen, skin, and
heart from the first case and from these and other viscera fragments in case 2.
RNA of yellow fever virus was identical to that previously described for 17D
genomic sequences. IgM ELISA tests for yellow fever virus were negative in case
1 and positive in case 2; similar tests for dengue, hantaviruses, arenaviruses,
Leptospira, and hepatitis viruses A-D were negative. Tissue injuries from both
patients were typical of wild-type yellow fever. INTERPRETATION: These serious
and hitherto unknown complications of yellow fever vaccination are extremely
rare, but the safety of yellow fever 17DD vaccine needs to be reviewed. Host
factors, probably idiosyncratic reactions, might have had a substantial
contributed to the unexpected outcome.
3194. Wu HC.
Huang YL. Chao TT. Jan JT.
Huang JL. Chiang HY. King CC.
Shaio MF. Identification of B-cell epitope of dengue virus type 1 and
its application in diagnosis of patients. Journal of Clinical
Microbiology. 39(3):977-82, 2001 Mar.
Abstract
Using a serotype-specific monoclonal antibody
(MAb) of dengue virus type 1 (DEN-1), 15F3-1, we identified the B-cell epitope
of DEN-1 from a random peptide library displayed on phage. Fourteen
immunopositive phage clones that bound specifically to MAb 15F3-1 were
selected. These phage-borne peptides had a consensus motif of HxYaWb (a = S/T,
b = K/H/R) that mimicked the sequence HKYSWK, which corresponded to amino acid
residues 111 to 116 of the nonstructural protein 1 (NS1) of DEN-1. Among the
four synthetic peptides corresponding to amino acid residues 110 to 117 of the
NS1 of DEN-1, -2, -3, and -4, only one peptide, EHKYSWKS (P14M) of DEN-1, was
found to bind to 15F3-1 specifically. Furthermore, P14M was shown to inhibit
the binding of phage particles to 15F3-1 in a competitive inhibition assay.
Histidine(111) (His(111)) was crucial to the binding of P14M to 15F3-1, since
its binding activity dramatically reduced when it changed to leucine(111)
(Leu(111)). This epitope-based peptide demonstrated its clinical diagnostic
potential when it reacted with a high degree of specificity with serum samples
obtained from both DEN-1-infected rabbits and patients. Based on these
observations, our DEN-1 epitope-based serologic test could be useful in
laboratory viral diagnosis and in understanding the pathogenesis of DEN-1.
3996. Barrett AD. Current status of flavivirus vaccines.
Ann N Y Acad Sci 2001 Dec;951:262-71
Although there are approximately 68 flaviviruses recognized, vaccines have been developed to control very few human flavivirus diseases. Licensed live attenuated vaccines have been developed for yellow fever (strain 17D) and Japanese encephalitis (strain SA14-14-2) viruses, and inactivated vaccines have been developed for Japanese encephalitis and tick-borne encephalitis viruses. The yellow fever live attenuated 17D vaccine is one of the most efficacious and safe vaccines developed to date and has been used to immunize more than 300 million people. A number of experimental vaccines are being developed, most notably for dengue. Candidate tetravalent live attenuated dengue vaccines are undergoing clinical trials. Other vaccines are being developed using reverse genetics, DNA vaccines, and recombinant immunogens. In addition, the yellow fever 17D vaccine has been used as a backbone to generate chimeric viruses containing the premembrane and envelope protein genes from other flaviviruses. The "Chimerivax" platform has been used to construct chimeric Japanese encephalitis and dengue viruses that are in different phases of development. Similar strategies are being used by other laboratories.
3997. Blaney JE Jr, Johnson DH, Firestone CY, Hanson
CT, Murphy BR, Whitehead SS. Chemical mutagenesis of dengue virus type 4 yields
mutant viruses which are temperature sensitive in vero cells or human liver
cells and attenuated in mice. J Virol
2001 Oct;75(20):9731-40
A recombinant live attenuated dengue virus type 4 (DEN4) vaccine candidate, 2ADelta30, was found previously to be generally well tolerated in humans, but a rash and an elevation of liver enzymes in the serum occurred in some vaccinees. 2ADelta30, a non-temperature-sensitive (non-ts) virus, contains a 30-nucleotide deletion (Delta30) in the 3' untranslated region (UTR) of the viral genome. In the present study, chemical mutagenesis of DEN4 was utilized to generate attenuating mutations which may be useful in further attenuation of the 2ADelta30 candidate vaccine. Wild-type DEN4 2A virus was grown in Vero cells in the presence of 5-fluorouracil, and a panel of 1,248 clones were isolated. Twenty ts mutant viruses were identified that were ts in both simian Vero and human liver HuH-7 cells (n = 13) or only in HuH-7 cells (n = 7). Each of the 20 ts mutant viruses possessed an attenuation phenotype, as indicated by restricted replication in the brains of 7-day-old mice. The complete nucleotide sequence of the 20 ts mutant viruses identified nucleotide substitutions in structural and nonstructural genes as well as in the 5' and 3' UTRs, with more than one change occurring, in general, per mutant virus. A ts mutation in the NS3 protein (nucleotide position 4995) was introduced into a recombinant DEN4 virus possessing the Delta30 deletion, thereby creating rDEN4Delta30-4995, a recombinant virus which is ts and more attenuated than rDEN4Delta30 virus in the brains of mice. We are assembling a menu of attenuating mutations that should be useful in generating satisfactorily attenuated recombinant dengue vaccine viruses and in increasing our understanding of the pathogenesis of dengue virus.
3998. Chang GJ, Davis BS, Hunt AR, Holmes DA, Kuno G.
Flavivirus DNA vaccines: current status and potential. Ann N Y Acad Sci 2001 Dec;951:272-85
The use of DNA-based vaccines is a novel and promising immunization approach for the development of flavivirus vaccines. This approach has been attempted in vaccine development for various virus species, including St. Louis encephalitis, Russian spring-summer encephalitis, Central European encephalitis, dengue serotypes 1 and 2, Murray Valley encephalitis, Japanese encephalitis, and West Nile viruses. However, very little is known about the factors affecting its efficacy. Recently, we demonstrated that a single intramuscular immunization of DNA vaccine of Japanese encephalitis and West Nile viruses protected mice and horses from virus challenge. Administration of these recombinant plasmid vectors resulted in endogenous expression and secretion of extracellular virus-like particles that correlated well with the induction of protective immunity. These results provided evidence that the virus-like particles composed of premembrane/membrane and envelope proteins are essential for eliciting immune responses similar to those induced by live, attenuated virus vaccines. The biosynthesis and protein processing of premembrane/membrane and envelope proteins that preserve the native conformation and glycosylation profiles identical to virion proteins could be determined by the effectiveness of the transmembrane signal sequence located at the amino-terminus of premembrane protein. The use of DNA vaccines in multivalent and/or combination vaccines designed to immunize against multiple flaviviruses is also a promising area of development.
3999. Cuzzubbo AJ, Endy TP, Nisalak A, Kalayanarooj S,
Vaughn DW, Ogata SA, Clements DE, Devine PL. Use of recombinant envelope
proteins for serological diagnosis of Dengue virus infection in an
immunochromatographic assay. Clin Diagn Lab Immunol 2001 Nov;8(6):1150-5
An immunochromatographic test that incorporates recombinant antigens (Dengue Duo Rapid Strip Test; PanBio, Brisbane, Australia) has recently become commercially available. This assay is performed in 15 min and detects both immunoglobulin M (IgM) and IgG in a capture format. The four recombinant proteins used represent the N-terminal 80% of the viral envelope glycoproteins of dengue viruses 1, 2, 3, and 4, respectively. The sensitivity and specificity of the recombinant-antigen-based assay were 90 and 86%, respectively. The similar diagnostic performance of these antigens to that of enzyme-linked immunosorbent assays using whole dengue virus suggests that they mimic whole dengue viruses in primary structure and epitope conformation. These results suggest that recombinant proteins can be used in diagnostic assays for dengue to overcome safety issues associated with the use of whole virus.
4000. Gomber S, Ramachandra n V G, Satish Kumar, Agarwal
K N, Gupta P, Gupta P, Dewan D K: Hematological observation as diagnostic
markers in dengue hemorrhagic fever. Indian Pediat 2001, 38(5),
477-81.(015304). Aug 1, 2001.
Determines the utility of certain clinical and hematological parameters as diagnostic markers of dengue hemorrhagic fever (DHF), namely, tourniquet test; association of bleeding manifestations with the platelet count, and “cut off” value of hematocrit diagnostic of DHF in Indian population. The tourniquet test had a low sensitivity and was positive only in 61/239 (25.5)% cases. There was no statistical difference in the incidence of bleeding manifestations between thrombocytopenic and non-thrombocytopenic individuals highlighting poor association of thrombocytopenia with bleeding manifestations. A “cut off” hematocrit value of 36.3% diagnostic of DHF was estimated discriminant analysis in Indian population. The study highlights tourniquet test as a less sensitive diagnostic marker of DHF, poor association of thrombocytopenia with bleeding manifestations and also defines the hematocrit value diagnostic of DHF in Indian populations. 14 ref.
4001. Huang JL, Huang JH, Shyu RH, Teng CW, Lin YL, Kuo
MD, Yao CW, Shaio MF. High level expression of recombinant dengue viral NS-1
protein and its potential use as a diagnostic antigen. J Med Virol 2001 Nov;65(3):553-60
The prevalence of NS1 Ab response in patients with dengue viral infection and the potential of using recombinant NS1 protein as a diagnostic antigen for dengue viral infection were investigated. In this study, the full-length and C-terminal half of NS1 proteins (rNS1, rNS1-C) were highly expressed (10-30 mg/l) and further purified and refolded. The good antigenicity of the full-length rNS1 protein was confirmed by interaction with 19 dengue NS1-specific monoclonal antibodies (MAbs) in ELISA; however, the antigenicity of rNS1-C was relatively lower. The full-length rNS1 antigen also differentiated reliably between sera from dengue virus-infected patients and sera from normal controls. When rNS1 was used as an antigen to detect human anti-NS1 IgM and IgG Ab, the anti-NS1 Ab response was found in 15 of 17 patients (88%) with primary dengue infection and all 16 patients (100%) with secondary dengue infection. These results indicated that using the full-length rNS1 whose antigenicity is restored as ELISA antigen, a high anti-NS1 antibody prevalence could be detected in patients with either primary or secondary dengue infection. This finding suggested that the anti-NS1 antibody appeared not only in secondary and severe dengue virus infection and might not correlate the pathogenesis of dengue hemorrhagic fever. The study also verified that our purified rNS1 protein showed similar immunological properties as native dengue viral proteins. Genetic engineering production of recombinant NS1 antigen could provide a safe and valuable resource for dengue virus serodiagnosis. Copyright 2001 Wiley-Liss, Inc.
4002. Openshaw PJ, Culley FJ, Olszewska W.
Immunopathogenesis of vaccine-enhanced RSV disease. Vaccine 2001 Oct 15;20 Suppl 1:S27-31
Inducing a strong immune response is an essential aim of vaccination. Although immune responses to virus infections are usually protective, they can also be harmful. The best-documented examples of an immune response increasing disease severity are with dengue, measles and respiratory syncytial virus infections.In the 1960s, administration of formalin-inactivated, tissue culture grown RSV (FI-RSV) was found to induce strong ELISA binding but poor virus-neutralising antibody. Infants given this 'lot 100' vaccine appeared to exhibit an increased rate of RSV infection during subsequent natural RSV outbreaks. Although it has not been possible to exactly delineate the cause of disease enhancement in man, animal models strongly suggest that it was due to strong (and perhaps unbalanced) T cell priming rather than infection-enhancing or sensitising antibody.In animal models, enhanced disease can result from over-exuberant T cell priming which recruits an abundant inflammatory infiltrate in the lung (the nature of which depends on the patterns of cytokines and chemokines produced). Formalin-treated RSV vaccination has been linked specifically to the induction of Th2 cells, which make IL-4 and IL-5 and induce a strong pulmonary eosinophilic response. The vaccine dosing regime and the interval between vaccination and challenge can be critical to the induction of protection or pathology. Defining the correlates of protection and disease enhancement in man is critical to the rational development of effective and protective vaccines against RSV.
4003. Pea L, Roda L, Moll F. Desmopressin treatment for
a case of dengue hemorrhagic fever/dengue shock syndrome. Clin Infect Dis 2001 Nov 1;33(9):1611-2 No
abstract.
4004. Troyer JM, Hanley KA, Whitehead SS, Strickman D,
Karron RA, Durbin AP, Murphy BR. A live attenuated recombinant dengue-4 virus
vaccine candidate with restricted capacity for dissemination in mosquitoes and
lack of transmission from vaccinees to mosquitoes. Am J Trop Med Hyg 2001 Nov;65(5):414-9
2Adelta30 is a live dengue-4 virus vaccine candidate with a 30-nucleotide deletion in its 3'-untranslated region. To assess the transmissibility of 2Adelta30 by mosquitoes, we compared its in vivo replication in mosquitoes with that of its wild type DEN-4 parent. Both the vaccine candidate and wild type virus were equally able to infect the mosquito Toxorhynchites splendens after intrathoracic inoculation. Relative to its wild type parent, 2Adelta30 was slightly restricted in its ability to infect the midgut of Aedes aegypti mosquitoes fed on an artificial blood meal and was even more restricted in its ability to disseminate from the midgut to the salivary glands. Thus, the 30-nucleotide deletion rendered the vaccine candidate more sensitive than its wild type parent to the mosquito midgut escape barrier. Most significantly, 2Adelta30 was not transmitted to 352 Ae. albopictus mosquitoes fed on 10 vaccinees, all of whom were infected with the vaccine candidate.
July 02
4540. Arora MM; Mishra KB; Nair V;
Bhardwaj JR; Bhalwar R; Somani BL. Diagnosing disseminated intravascular
coagulation in acute infection : can we do without FDP & D-DIMER Medical
Journal Armed Forces India 2002 Jan; 58(1): 13-7
ABSTRACT: Alterations in coagulation
profile viz. platelet count, prothrombin time (PT), partial thromboplastin time
with kaolin (PTTK), thrombin time (TT) and fibrinogen were studied in 96
patients (73 males and 23 females) of acute infections. Fibrin/fibrinogen
degradation products (FDP) level >25miug fibrinogen equivalent unit (FEU)/ml
along-with D-dimer >1.0miug FEU/ml was considered criteria for diagnosis of
disseminated intravascular coagulation (DIC). Normal values were established
using plasma from 12 healthy voluntary blood donors. Out of these 96 patients,
15 had infection with Gram positive bacteria, 23 with Gram negative bacteria
and 38 with Dengue. In 20 patients, nature of infection was not defined. Mean platelet
count per cubic millimeter was 2.14 lac in Gram positive infection and 1.74 lac
in Gram negative infection (p=0.07). There was no significant difference in
other coagulation parameters in Gram positive and Gram negative infection.
Platelet counts were low in 71 percent of Dengue patients but there was no significant
alteration in PT, PTTK and TT. None of the Dengue patients had
hypofibrinogenemia or DIC though hyperfibrinogenemia was present in 21 percent
of Dengue patients.
20 patients had features of septicemia (Gram +ve 7, Gram-ve 8, undefined 5); 10
had concomitant DIC. DIC was present in additional 4 patients of acute
infection without septicemia. PTTK was raised in 60 percent of the septicemia
patients. 20 out of 82 non-DIC acute infection patients had subnormal PTTK.
Commonest alteration in 14 DIC patients was raised PTTK with a sensitivity of
78.6 percent and specificity of 81.7 percent. Low fibrinogen levels though
specific for DIC, were present in only 21.4 percent of the DIC patients.
Combinations of PTTK >38 sec with PT>15 sec or platelet count <1.5 lac/mm
cube were good screening tests for DIC and detected 11 and 10 patients out of
14 with three and two false positives respectively.
4541. Cao XT,
Ngo TN, Wills B, Kneen R, Nguyen TT, Ta TT, Tran TT, Doan TK, Solomon T,
Simpson JA, White NJ, Farrar JJ. Evaluation of the World Health Organization
standard tourniquet test and a modified tourniquet test in the diagnosis of
dengue infection in Viet Nam. Trop Med Int Health. 2002 Feb;7(2):125-32.
OBJECTIVES: A positive
tourniquet test is one of several clinical parameters considered by the World
Health Organization to be important in the diagnosis of dengue haemorrhagic
fever, but no formal evaluation of the test has been undertaken. As many
doctors remain unconvinced of its usefulness, this study was designed to assess
the diagnostic utility of both the standard test and a commonly employed
modified test. METHODS: A prospective evaluation of the standard
sphygmomanometer cuff tourniquet test, compared with a simple elastic cuff
tourniquet test, was carried out in 1136 children with suspected dengue
infection admitted to a provincial paediatric hospital in southern Viet Nam.
RESULTS: There was good agreement between independent observers for both
techniques, but the sphygmomanometer method resulted in consistently greater
numbers of petechiae. This standard method had a sensitivity of 41.6% for
dengue infection, with a specificity of 94.4%, positive predictive value of
98.3% and negative predictive value of 17.3%. The test differentiated poorly
between dengue haemorrhagic fever (45% positive) and dengue fever (38%
positive). The simple elastic tourniquet was less sensitive than the
sphygmomanometer cuff, but at a threshold of 10 petechiae (compared with the
WHO recommendation of 20) per 2.5 cm2 the sensitivity for the elastic
tourniquet rose to 45% (specificity 85%). Other evidence of bleeding was
frequently present and the tourniquet test provided additional information to
aid diagnosis in only 5% of cases. CONCLUSION: The conventional tourniquet test
adds little to the diagnosis of dengue in hospitalized children. The simple,
cheap elastic tourniquet may be useful in diagnosing dengue infection in busy
rural health stations in dengue endemic areas of the tropics. A positive test
should prompt close observation or early hospital referral, but a negative test
does not exclude dengue infection.
4542. da
Fonseca BA, Fonseca SN. Dengue virus infections. Curr Opin Pediatr. 2002
Feb;14(1):67-71. Review.
Dengue is the most important arthropod-borne viral disease of public health significance. Its geographic distribution includes more than 100 countries worldwide, where more than 2.5 billion people are at risk for dengue infections. Most people will have asymptomatic infections, but the disease manifestations range from an influenza-like disease known as dengue fever to a severe, sometimes fatal disease characterized by hemorrhage and shock, known as dengue hemorrhagic fever/dengue shock syndrome. Dengue fever and dengue hemorrhagic fever/dengue shock syndrome are caused by the dengue viruses (dengue-1, dengue-2, dengue-3, and dengue-4) transmitted from viremic to susceptible humans mainly by the bites of Aedes aegypti. There is no specific management of dengue infections, no vaccine is commercially available, and vector control is the only alternative for stopping the spread of the disease. Knowledge of several aspects of dengue infections, especially of diagnosis and vaccine development, is continuously evolving, but several issues are still unresolved.
4543. Gasem
MH, Smits HL, Goris MG, Dolmans WM. Evaluation of a simple and rapid dipstick
assay for the diagnosis of typhoid fever in Indonesia. J Med Microbiol. 2002
Feb;51(2):173 7.
To support the clinical diagnosis of typhoid fever in Indonesia, where most hospitals and health centres have no facilities for culture, a rapid dipstick assay for the detection of Salmonella typhi-specific IgM antibodies was evaluated on serum samples from 127 patients clinically suspected of having typhoid fever. In a single blood sample collected on admission to hospital, the sensitivity of the dipstick assay was 69.8% when compared with bone marrow culture and 86.5% when compared with blood culture. The specificity as calculated for the group of patients with suspected typhoid fever but a negative culture result was calculated to be 88.9%. Of 80 patients with febrile illnesses other than typhoid fever, reactivity was observed in only three patients with dengue haemorrhagic fever. The assay uses stabilised components that can be stored outside the refrigerator, does not require special equipment, and may be of use in remote health facilities that have no culture facilities.
4544. Guzman
MG, Kouri G. Dengue: an update.Lancet Infect Dis. 2002 Jan;2(1):33-42. Review.
This review is an update of dengue and dengue haemorrhagic fever (DHF) based on international and Cuban experience. We describe the virus characteristics and risk factors for dengue and DHF, and compare incidence and the case fatality rates in endemic regions (southeast Asia, western Pacific, and the Americas). The clinical picture and the pathogenesis of the severe disease are explained. We also discuss the viral, individual, and environmental factors that determine severe disease. Much more research is necessary to clarify these mechanisms. Also reviewed are methods for viral isolation and the serological, immunohistochemical, and molecular methods applied in the diagnosis of the disease. We describe the status of vaccine development and emphasise that the only alternative that we have today to control the disease is through control of its vector Aedes aegypti.
4545. Monath
TP, Arroyo J, Levenbook I, Zhang ZX, Catalan J, Draper K, Guirakhoo F. Single
mutation in the flavivirus envelope protein hinge region increases
neurovirulence for mice and monkeys but decreases viscerotropism for monkeys:
relevance to development and safety testing of live, attenuated vaccines. J
Virol. 2002 Feb;76(4):1932-43.
A chimeric yellow fever (YF) virus/Japanese encephalitis (JE) virus vaccine (ChimeriVax-JE) was constructed by insertion of the prM-E genes from the attenuated JE virus SA14-14-2 vaccine strain into a full-length cDNA clone of YF 17D virus. Passage in fetal rhesus lung (FRhL) cells led to the emergence of a small-plaque virus containing a single Met-->Lys amino acid mutation at E279, reverting this residue from the SA14-14-2 to the wild-type amino acid. A similar virus was also constructed by site-directed mutagenesis (J. Arroyo, F. Guirakhoo, S. Fenner, Z.-X. Zhang, T. P. Monath, and T. J. Chambers, J. Virol. 75:934-942, 2001). The E279 mutation is located in a beta-sheet in the hinge region of the E protein that is responsible for a pH-dependent conformational change during virus penetration from the endosome into the cytoplasm of the infected cell. In independent transfection-passage studies with FRhL or Vero cells, mutations appeared most frequently in hinge 4 (bounded by amino acids E266 to E284), reflecting genomic instability in this functionally important region. The E279 reversion caused a significant increase in neurovirulence as determined by the 50% lethal dose and survival distribution in suckling mice and by histopathology in rhesus monkeys. Based on sensitivity and comparability of results with those for monkeys, the suckling mouse is an appropriate host for safety testing of flavivirus vaccine candidates for neurotropism. After intracerebral inoculation, the E279 Lys virus was restricted with respect to extraneural replication in monkeys, as viremia and antibody levels (markers of viscerotropism) were significantly reduced compared to those for the E279 Met virus. These results are consistent with the observation that empirically derived vaccines developed by mouse brain passage of dengue and YF viruses have increased neurovirulence for mice but reduced viscerotropism for humans.
Oct 2002
5218.
Bartley LM,
Carabin H, Vinh Chau N, Ho V, Luxemburger C, Hien TT, Garnett GP, Farrar J.
Assessment of the factors associated with flavivirus seroprevalence in a
population in Southern Vietnam. Epidemiol Infect. 2002 Apr;128(2):213-20.
Dengue and Japanese encephalitis
flaviviruses cause severe disease and are hyperendemic in southern Vietnam.
This study assesses associations between sociodemographic factors and
flavivirus seroprevalence in this region. Sera were collected from 308
community and hospital-based subjects between April 1996 and August 1997 and
tested with an indirect ELISA. The factors associated with seroprevalence were
assessed using multivariate logistic regression. In this first report of
adjusted prevalence odds ratios (POR) for flavivirus infection in Vietnam,
seropositivity was associated with increasing age in children (multiple
regression coefficients for a child compared to an adult = -4.975 and for age
in children = 0.354) and residence in the city compared to surrounding rural
districts. The association with age indicates that subjects were most likely to
have acquired infection in early childhood. This is key to the design of
Vietnamese health education and immunization programmes.
5219.
Branch SL,
Levett PN. Evaluation of four methods for detection of immunoglobulin M
antibodies to dengue virus. Clin Diagn Lab Immunol. 1999 Jul;6(4):555-7.
Dengue has become hyperendemic in many
islands of the Caribbean region. The performance in a diagnostic laboratory of
four commercial assays for detection of immunoglobulin M (IgM) antibodies was
evaluated. Sera from 62 patients with dengue virus infection were studied.
These included 18 patients from whom dengue virus type 2 was isolated in a 1997
outbreak (specimens collected a mean of 14 days after onset of symptoms), 8
patients with dengue hemorrhagic fever (mean time after onset, 11 days), and 36
patients in whom dengue was previously confirmed by serology (mean time after
onset, 10 days). Thirty serum specimens from blood donors in a country where
dengue is not endemic were used as negative controls. The methods evaluated
were two IgM-capture enzyme-linked immunosorbent assays (ELISA) (MRL
Diagnostics, Cypress, Calif., and PanBio, Queensland, Australia), a dot ELISA
dipstick assay (Integrated Diagnostics, Baltimore, Md.), and a rapid
immunochromatographic assay for dengue IgG and IgM (PanBio IC). IgG antibodies
were also detected by an ELISA method (MRL Diagnostics). The sensitivities of
the four assays were as follows: MRL Diagnostics IgM ELISA, 98.4%; PanBio IgM
ELISA, 85.5%; Integrated Diagnostics IgM dot ELISA, 96. 8%; and PanBio IC,
83.9%. The specificities of all tests were 100%. Evidence of secondary dengue
was found in all patients with dengue hemorrhagic fever and in 83% of the
remaining patients. The MRL Diagnostics IgM ELISA appears to be more sensitive
than the PanBio IgM ELISA, and this may be significant when IgM titers are low,
particularly in patients with secondary dengue infections. The dot ELISA
dipstick assay is equally sensitive and may be more appropriate for use in
laboratories with lower workloads.
5220.
De Paula SO,
Lopes da Fonseca BA. Optimizing dengue diagnosis by RT-PCR in IgM-positive
samples: comparison of whole blood, buffy-coat and serum as clinical samples. J
Virol Methods. 2002 Apr;102(1-2):113-7.
Dengue, a major public health problem in
tropical and sub-tropical regions, is the most important arboviral disease of
humans. Early diagnosis is very important on follow-up of infected patients,
especially those at risk of the severe manifestations of this disease. Aiming
at the improvement of the molecular diagnosis of these infections and due to
the lack of studies that indicated the best sample for dengue virus detection
by RT-PCR, viral detection by RT-PCR in blood, serum and buffy-coat of 75
IgM-positive serum samples for dengue was evaluated. Out of the 75 samples, 17
were positive for dengue using RT-PCR and from these samples, three were positive
in the blood, 14 positive in the serum and eight positive in the buffy-coat.
These results indicate that serum is the best clinical sample for RT-PCR
amplification of dengue genomes.
5221.
Groen J,
Koraka P, Velzing J, Copra C, Osterhaus AD. Evaluation of six immunoassays for
detection of dengue virus-specific immunoglobulin M and G antibodies. Clin
Diagn Lab Immunol. 2000 Nov;7(6):867-71.
The performance of six commercially
available immunoassay systems for the detection of dengue virus-specific
immunoglobulin M (IgM) and IgG antibodies in serum was evaluated. These
included two IgM and IgG enzyme immunoassays (EIA) from MRL Laboratories and
PanBio, a rapid immunochromatographic test (RIT) from PanBio,
immunofluorescence assays (IFA) from Progen, a dot blot assay from Genelabs,
and a dipstick EIA from Integrated Diagnostics (INDX). For this study a panel
of 132 serum samples, including 90 serum samples from patients with suspected
dengue virus infection and 42 serum samples from patients with other viral infections,
was used. In addition, serial serum samples from two monkeys experimentally
immunized and challenged with dengue virus type 2 were used. Results were
considered conclusive when concordant results were obtained with four of the
six antibody-specific assays. Based on this definition, the calculated overall
agreement for the human serum samples for the respective IgM immunoassays was
97% (128 of 132), with 34% (45 of 132) positive serum samples, 63% (83 of 132)
negative samples, and 3% of samples (4 of 132) showing discordant results. The
calculated overall agreement for the IgG assays was 94% (124 of 132), with 49%
(65 of 132) positive, 45% (59 of 132) negative, and 6% (8 of 132) discordant
results, respectively. The sensitivities of the dengue virus-specific assays
evaluated varied between 71 and 100% for IgM and between 52 and 100% for IgG,
with specificities of 86 to 96% and 81 to 100%, respectively. The relative
sensitivities of the respective IgM assays measured with the monkey serum
samples were comparable with those obtained with 12 serial serum samples from
humans. Overall performance, based on the sum of the agreement, sensitivity,
specificity, and Kappa statistics of the IgM and IgG immunoassays, showed that
the antibody detection systems from INDX and Genelabs and the MRL and PanBio
EIA are useful and reliable assays for dengue virus serodiagnosis.
5222.
Lum LC, Goh
AY, Chan PW, El-Amin AL, Lam SK. Risk factors for hemorrhage in severe dengue
infections. J Pediatr. 2002 May;140(5):629-31.
The purpose of this study was to identify
the early indicators of hemorrhage in severe dengue infections in 114 patients;
24 patients had severe hemorrhage and 92 had no hemorrhage. The platelet counts
were not predictive of bleeding. The duration of shock (OR, 2.11; 95% CI, 1.13
to 3.92; P =.019) and low-normal hematocrit at the time of shock (OR, 0.72; 95%
CI, 0.55 to 0.95; P =.020) were risk factors of severe hemorrhage.
5223.
Palmer CJ,
King SD, Cuadrado RR, Perez E, Baum M, Ager AL. Evaluation of the MRL
diagnostics dengue fever virus IgM capture ELISA and the PanBio Rapid
Immunochromatographic Test for diagnosis of dengue fever in Jamaica. J Clin
Microbiol. 1999 May;37(5):1600-1.
We evaluated two new commercial dengue
diagnostic tests, the MRL Diagnostics Dengue Fever Virus IgM Capture ELISA and
the PanBio Rapid Immunochromatographic Test, on serum samples collected during
a dengue epidemic in Jamaica. The MRL ELISA method correctly identified 98% (78
of 80) of the samples as dengue positive, while the PanBio test identified 100%
(80 of 80). Both tests were 100% (20 samples of 20) specific.
5224.
Porter KR,
Widjaja S, Lohita HD, Hadiwijaya SH, Maroef CN, Suharyono W, Tan R. Evaluation of a commercially available
immunoglobulin M capture enzyme-linked immunosorbent assay kit for diagnosing
acute dengue infections. Clin Diagn Lab Immunol. 1999 Sep;6(5):741-4.
Recently, commercially available kits for
the detection of anti-dengue virus (anti-DEN) immunoglobulin M (IgM) antibodies
have been developed. These standardized assays have greatly enhanced our
ability to effectively diagnose DEN infections. We conducted an evaluation of a
test kit manufactured by MRL Diagnostics Inc. that is designed to detect
anti-DEN IgM antibodies. Eighty paired samples from DEN-infected individuals
were tested by the MRL DEN Fever Virus IgM Capture enzyme-linked immunosorbent
assay (ELISA), the PanBio Duo ELISA, the PanBio Rapid Immunochromatographic
Test (PRIT), and the IgM-IgG antibody capture (MAC/GAC) ELISA. All infections
were confirmed by either PCR-assisted detection of DEN transcripts or by DEN
isolation in C6/36 cells. Seventeen paired samples from individuals with no
evidence of acute DEN infection were used as negative controls. The PRIT had
the best sensitivity (100%), whereas the MAC/GAC ELISA and the PanBio Duo assay
had the highest levels of specificity. The MRL ELISA and the PanBio Duo assay
were the top performers when taking into consideration both sensitivity and
specificity. All assays were able to detect DEN-specific antibodies in samples
from patients with either primary or secondary infections, regardless of the
infecting DEN serotype.
5225.
Spiegel J,
Yassi A, Tate R. Dengue in Cuba: mobilisation against Aedes aegypti. Lancet
Infect Dis. 2002 Apr;2(4):207-8. No
abstract.
5226.
van Gorp EC,
Suharti C, Mairuhu AT, Dolmans WM, van Der Ven J, Demacker PN, van Der Meer JW.
Changes in the plasma lipid profile as a potential predictor of clinical
outcome in dengue hemorrhagic fever. Clin Infect Dis. 2002 Apr 15;34(8):1150-3.
In 50 consecutive children admitted to the
intensive care unit with the clinical diagnosis of dengue hemorrhagic fever
(DHF)/dengue shock syndrome (grade III or IV), 20 patients with mild DHF (grade
I or II), and 20 healthy control patients, the plasma lipid profile was
measured. Levels of total plasma cholesterol, high-density lipoprotein, and
low-density lipoprotein were significantly decreased in patients with the
severest cases, compared with patients with mild DHF and healthy controls.
Changes in the plasma lipid profile differentiate between patients with
different stages of DHF disease severity and could be used as a potential
predictor for clinical outcome.
5227.
Vaughn DW,
Endy TP. Hospital-based diagnosis of hemorrhagic fever, encephalitis, and
hepatitis in Cambodian children. Emerg Infect Dis. 2002 May;8(5):485-9.
Surveillance was conducted for three
clinical syndromes (hemorrhagic fever, encephalitis, and hepatitis) in
Cambodian children admitted to the National Pediatric Hospital in Phnom Penh
from July 1996 through September 1998. Acute- and convalescent-phase sera, and
cerebrospinal fluid, when applicable, underwent diagnostic evaluation for
infections with Dengue virus (DENV), Japanese encephalitis virus (JEV), and
Hepatitis A, B, C, and E viruses. Of 621 children admitted with hemorrhagic
fever, 499 (80%) were confirmed to have either primary or secondary DENV
infection. DENV rates were as high as 10.6/100 hospital admissions in September
1998. Of 50 children with clinical encephalitis, 9 (18%) had serologic evidence
of JEV infection. Forty-four children had clinical hepatitis, most (55%) due to
Hepatitis A virus (HAV). One patient had Hepatitis B virus, and no patients had
hepatitis C or E. This study identified a large number of children with vaccine-preventable
diseases (JEV and HAV).
5228.
Warrilow D,
Northill JA, Pyke A, Smith GA. Single rapid TaqMan fluorogenic probe based PCR
assay that detects all four dengue serotypes. J Med Virol. 2002
Apr;66(4):524-8.
Public health laboratories require rapid
diagnosis of dengue outbreaks for application of measures such as vector
control. We have developed a rapid single fluorogenic probe-based polymerase
chain reaction assay for the detection of all four dengue serotypes
(FUDRT-PCR). The method employs primers and probe that are complementary to the
evolutionarily conserved 3' untranslated region of the dengue genome. The assay
detected viral RNA of strains of all four dengue serotypes but not of the
flaviviruses Japanese encephalitis virus, Murray Valley encephalitis virus,
Kunjin, Stratford, West Nile, Alfuy or Yellow fever. When compared to an
existing nested-PCR assay for the detection of dengue on clinical samples,
FUDRT-PCR detected dengue 1 (100%, n=14), dengue 2 (85%, n=13), dengue 3 (64%,
n=14) and dengue 4 (100%, n=3) with the indicated sensitivities. FUDRT-PCR
enables diagnosis of acute dengue infection in four hours from sample receipt.
In addition, a single-test procedure should result in a reduction in the number
of tests performed with considerable cost savings for diagnostic laboratories.
Copyright 2002 Wiley-Liss, Inc.
5229. Wu SJ, Paxton H, Hanson B, Kung CG, Chen TB, Rossi C, Vaughn DW, Murphy GS, Hayes CG. Comparison of two rapid diagnostic assays for detection of immunoglobulin M antibodies to dengue virus. Clin Diagn Lab Immunol. 2000 Jan;7(1):106-10.
Two easy-to-use commercial diagnostic
assays, a dipstick enzyme-linked immunosorbent assay (ELISA) (Integrated
Diagnostics, Baltimore, Md.) and an immunochromatographic card assay (PanBio,
Brisbane, Australia) were evaluated for detection of immunoglobulin M (IgM)
antibody to dengue virus with an in-house IgM antibody capture microplate ELISA
as a reference assay. The dipstick ELISA was based on the indirect-ELISA format
using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human IgM
antibody as the detector. The total assay time was 75 min. The
immunochromatographic card assay was based on the antibody capture format and
separately measured both anti-dengue virus IgM and IgG in the same test.
Colloidal-gold-labeled anti-dengue virus monoclonal antibody bound with dengue
virus 1 to 4 antigen cocktail was the detector, and anti-human IgM and IgG were
the capture antibodies. The total assay time was <10 min. Sera from 164
individuals classified as either anti-dengue virus IgM positive (94) or
anti-dengue virus IgM negative (70) in the reference microplate ELISA with a
dengue virus 1 to 4 antigen cocktail were tested in the two commercial assays.
The dipstick ELISA missed 7 of 94 positive samples, for a sensitivity of 92.6%,
while the immunochromatographic card assay missed two positive samples, for a
sensitivity of 97.9%. Of the 70 negative samples, four were false positive by
the dipstick ELISA and two were false positive in the immunochromatographic
card assay, resulting in specificities of 94.3 and 97.1%, respectively. Both
commercial assays provide sensitive and specific detection of anti-dengue virus
IgM antibody and could prove useful in settings where the microplate ELISA is
impractical.
5230.
Yamada K,
Takasaki T, Nawa M, Kurane I. Virus isolation as one of the diagnostic methods
for dengue virus infection. J Clin Virol. 2002 Apr;24(3):203-9.
Virus isolation is the most reliable
evidence of infection. In the present study, we isolated virus from serum
samples collected from confirmed denguecases. When data were analyzed based on
disease days, dengue viruses were isolated from 28 of 32 serum samples
collected on disease day 5 or earlier. When analyzed based on fever days,
dengue viruses were isolated from all the serum samples collected on fever day
-3 or earlier, and from 10 of 13 samples collected on fever days -2 and -1.
Viruses were isolated from one each of the serum samples collected on fever
days 0, 1, 2 and 3, respectively. Virus was not, however, isolated from those
collected on fever day 4 or later. The results of virus isolation and reverse
transcriptase-polymerase chain reaction were consistent in 78 of 82 serum
samples. These results suggest that virus isolation is a useful and sensitive
technique for confirmation of dengue virus infection, especially when serum
samples are collected before fever subsides.
Pathogenesis:
5231.
Wang WK, Lin
SR, Lee CM, King CC, Chang SC. Dengue type 3 virus in plasma is a population of
closely related genomes: quasispecies. J Virol. 2002 May;76(9):4662-5.
Using reverse transcription-PCR and clonal
sequencing of the dengue virus envelope gene derived from the plasma samples of
six patients, we reported for the first time that dengue virus circulates as a
population of closely related genomes. The extent of sequence diversity varied
among patients, with the mean pairwise proportions of difference ranging from
0.21 to 1.67%. Genome-defective viruses were found in 5.8% of the total number
of clones analyzed. Our findings on the quasispecies nature of dengue virus and
the defective virus in vivo have implications with regard to the pathogenesis
of dengue virus.
Vaccines :
5232. Clarke T. Dengue virus: break-bone fever. Nature 2002 Apr 18;416(6882):672-4 No abstract.