Emergence of human West Nile Virus infection in Sri Lanka

Lohitharajah, Janarthani; Malavige, Gathsaurie Neelika; Chua, Anthony Jin Shun; Ng, Mah Lee; Arambepola, Carukshi; Chang, Thashi

doi:10.1186/s12879-015-1040-7

Cited by 14 publications

(17 citation statements)

References 20 publications

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“…Although seizures are described as uncommon in West Nile virus infection [ 30 , 31 ], Case 1 and Case 3 of our series had generalized tonic-clonic seizures. This is similar to a study described in 2015 from Sri Lanka [ 32 ]. None of the cases had history of diarrhoea, rash, or vomiting as quoted in the literature.…”

Section: Discussionsupporting

confidence: 92%

Clinical Features of Four West Nile Virus Cases and Its Molecular Characterization from a South Indian Tertiary Care Hospital

Mammen

Nair

Kumar

et al. 2020

Case Reports in Infectious Diseases

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West Nile virus (WNV) is currently a significant reemerging virus of the 21st century. It belongs to the family Flaviviridae and genus Flavivirus. Although it is primarily transmitted by the Culex spp of mosquitoes, other routes of transmission are also well defined. Of eight lineages described, Lineage 1a has been reported from many parts of South India and is known to cause neuroinvasive illness. Many tests and serological techniques have been described to diagnose WNV infection such as complement fixation, neutralization, heamagglutination inhibition, ELISA, and PCR for molecular confirmation. The latter far outweighs the limitations inherent in the other tests. WNV infection is being reported from Vellore for the first time after 1968. This paper aims to describe four cases of WNV infection causing central nervous system manifestations with its molecular characterization. West Nile virus infection was diagnosed with the available molecular techniques such as PCR and sequencing, which emphasizes the need for considering West Nile virus in the differential diagnosis of acute meningoencephalitis and the wider availability of molecular diagnostic tests.

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Section: Discussionsupporting

confidence: 92%

Clinical Features of Four West Nile Virus Cases and Its Molecular Characterization from a South Indian Tertiary Care Hospital

Mammen

Nair

Kumar

et al. 2020

Case Reports in Infectious Diseases

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“…However, there were no distinguishing clinical characteristics in the WNV infected patients [17]. The presence of neutrophil predominance in CSF has been suggested as a possible diagnostic clue of WNV infection [26], but only one of our three patients had CSF neutrophilic pleocytosis.…”

Section: Discussionmentioning

confidence: 80%

Viral aetiologies of acute encephalitis in a hospital-based South Asian population

Lohitharajah¹,

Malavige

Arambepola

et al. 2017

BMC Infect Dis

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BackgroundThe aetiological spectrum of acute encephalitis shows inter- and intra-geographical variations. We aimed to identify the viruses that cause infectious encephalitis in Sri Lanka, which represents a South Asian population.MethodsA cross-sectional study was conducted among 99 patients with encephalitis/meningoencephalitis admitted to two tertiary-care hospitals in Colombo. Cerebrospinal fluid and serum were tested for conventional and emerging encephalitogenic viruses. Specific nucleic acid amplification and antibody assays were used to identify viruses. Plaque reduction neutralization test was done to confirm the diagnosis of West Nile virus (WNV).ResultsPatients’ age ranged from 1 month to 73 years (mean = 24.91; SD = 21.33) with a male:female ratio of 1.75:1. A viral aetiology was identified in only 27.3%. These included dengue virus (40.7%), Japanese encephalitis virus (25.9%), varicella zoster virus, WNV and probable Epstein Barr virus (11.1% each). None were positive for herpes simplex viruses or cytomegalovirus. Screening for bacterial aetiologies was negative for all patients. There were no distinguishable clinical or laboratory findings between the different viral aetiologies. The case fatality rate was 7%, which was higher among patients with an identified viral aetiology.ConclusionsA viral aetiology was identified in only about a quarter of patients with encephalitis. Dengue virus accounted for the majority.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2403-z) contains supplementary material, which is available to authorized users.

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“…Infection with either Zika or yellow fever virus has not been reported in Sri Lanka so far. However, sporadic cases of West Nile virus (WNV) have been reported (3,40) and JEV-peptide 34 gives a 40% homology with the WNV, which could induce crossreactive T cells. Two of the peptides (peptide 2 and 3) which were identified within envelope region of JEV and which did not induce any responses in DENV seropositive individuals, showed 55% homology with WNV.…”

Section: Discussionmentioning

confidence: 99%

“…Although case fatality rates due to dengue are declining in many countries including Sri Lanka, the rates are still significantly high in countries such as India, where the case fatality rates are estimated to be 2.6% (2). Other flavivirus infections such as the Japanese Encephalitis virus (JEV) and the West Nile virus (WNV), co-circulate in the same geographical regions such as DENV (3,4), and due to the similarity between these viruses, have a potential to modulate the immune responses to each other. Natural infection with JEV has shown to generate highly cross reactive T cell responses that has a potential to lead to either milder or more severe disease when infected with DENV (5).…”

Section: Introductionmentioning

confidence: 99%

Identification of Immune Responses to Japanese Encephalitis Virus Specific T Cell Epitopes

Pushpakumara

Jeewandara

Wijesinghe

et al. 2020

Front. Public Health

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Background: Due to the similarity between the dengue (DENV) and the Japanese encephalitis virus (JEV) there is potential for immune cross-reaction. We sought to identify T cell epitopes that are specific to JEV and do not cross react with DENV.Methodology: 20mer peptides were synthesized from regions which showed >90% conservation. Using IFNγ cultured ELISpot assays, we investigated JEV-specific T cell responses in DENV − and JEV − non-immune individuals (DENV − JEV − = 21), JEV seronegative and had not received the JE vaccine, but who were DENV seropositive (DENV + JEV − = 22), JEV + (seropositive for JEV and had received the JE vaccine), but seronegative for DENV (DENV − JEV + = 23). We further assessed the responses to these peptides by undertaking ex vivo IFNγ assays and flow cytometry.Results: None of DENV − JEV − individuals responded to any of the 20 JEV-specific peptides. High frequency of responses was seen to 6/20 peptides by individuals who were JEV + but DENV − , where over 75% of the individuals responded to at least one peptide. P34 was the most immunogenic peptide, recognized by 20/23 (86.9%) individuals who were DENV − JEV + , followed by peptide 3 and peptide 7 recognized by 19/23 (82.6%). Peptide 34 from the NS2a region, showed <25% homology with any flaviviruses, and <20% homology with any DENV serotype. Peptide 20 and 32, which were also from the non-structural protein regions, showed <25% homology with DENV. Ex vivo responses to these peptides were less frequent, with only 40% of individuals responding to peptide 34 and 16-28% to other peptides, probably as 5/6 peptides were recognized by CD4+ T cells.Discussion: We identified six highly conserved, T cell epitopes which are highly specific for JEV, in the Sri Lankan population. Since both JEV and DENV co-circulate in the same regions and since both JE and dengue vaccines are likely to be co-administered in the same geographical regions in future, these JEV-specific T cell epitopes would be useful to study JEV-specific T cell responses, in order to further understand how DENV and JEV-specific cellular immune responses influence each other.

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Emergence of human West Nile Virus infection in Sri Lanka

Cited by 14 publications

References 20 publications

Clinical Features of Four West Nile Virus Cases and Its Molecular Characterization from a South Indian Tertiary Care Hospital

Clinical Features of Four West Nile Virus Cases and Its Molecular Characterization from a South Indian Tertiary Care Hospital

Viral aetiologies of acute encephalitis in a hospital-based South Asian population

Identification of Immune Responses to Japanese Encephalitis Virus Specific T Cell Epitopes

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