ABSTRACT
Kyasanur forest disease (KFD) is a zoonotic viral disease caused by infection by a Flavivirus, a member of the family Flaviviridae. KFD is a public health concern in the Karnataka State in southern India. Available conventional diagnostic tests such as virus isolation and serological tests, such as haemagglutination inhibition and complement fixation tests are time consuming. This study reports the development of a nested RT-PCR [nRT-PCR] and a TaqMan-based real-time RT-PCR and IgM antibodies capture ELISA [MAC-ELISA] for rapid and accurate diagnosis of suspected KFD cases. The nRT-PCR and the TaqMan-based real-time RT-PCR assays were developed using gene sequences of the NS-5/non-coding region. Both the assays detected KFD viral RNA in acute phase human serum samples and can provide early diagnosis of infection. Real-time RT-PCR was found to be more sensitive than nRT-PCR, which could detect 38 copies of KFDV RNA. MAC-ELISA was developed for the detection of recent infections. Although real-time RT-PCR and nRT-PCR require expensive reagents, expensive equipment and trained personnel, the developed MAC-ELISA can be used easily in the affected areas. These tests add to the existing diagnosis arsenal against haemorrhagic viruses that are prevalent in India. These assays will also help to extend our knowledge of the pathology of KFD virus and its associated clinical features, by measuring the viral titre during infection and at the time of seroconversion. Information, which is not available currently because of the lack of appropriate diagnostic methods. In addition, early laboratory diagnosis of KFDV infection will help in the application of appropriate control measures and management of KFD cases.
Subject(s)
Antibodies, Viral/blood , Immunoglobulin M/blood , Kyasanur Forest Disease/diagnosis , Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Enzyme-Linked Immunosorbent Assay/methods , Flavivirus/genetics , Flavivirus/immunology , Humans , India , Sensitivity and SpecificityABSTRACT
An outbreak of encephalitis with a case fatality rate of 78.3% was investigated among children in Gujarat State, India. Twenty-six cases were reported. Three patients had IgM antibodies to Chandipura virus. Virus was isolated from one patient with rhabdomyosarcoma in porcine stable cell lines and in suckling mice. Chandipura virus RNA was present in 9 of 20 acute-phase serum samples, and virus sequences from the present outbreak were closely related to prototype strain (1965) and Andhra Pradesh, India (2003) isolates. Serologic and molecular assays documented the absence of Japanese encephalitis virus, West Nile virus, dengue virus, and paramyxoviruses in clinical samples. The etiologic agent was Chandipura virus, which has become an important encephalitis-causing virus in India.
Subject(s)
Rhabdoviridae Infections/epidemiology , Vesiculovirus , Adolescent , Antibodies, Viral/blood , Child , Child, Preschool , Disease Outbreaks , Female , Humans , Immunoglobulin M/blood , India/epidemiology , Infant , Male , Phylogeny , RNA, Viral/blood , Vesiculovirus/genetics , Vesiculovirus/isolation & purificationABSTRACT
BACKGROUND: An outbreak of acute encephalitis of unknown origin with high case fatality (183 of 329 cases) was reported in children from Andhra Pradesh state in southern India during 2003. We investigated the causative agent. METHODS: Cell lines and peripheral blood lymphocyte co-cultures were used to isolate the causative agent from clinical samples. Identity of the agent was established by electron microscopy and serological and molecular assays. FINDINGS: Clinical samples tested negative for IgM antibodies to Japanese encephalitis, West Nile, dengue, and measles viruses, and for RNA of coronavirus, paramyxovirus, enterovirus, and influenza viruses. Virus was isolated from six patients with encephalitis and was identified as Chandipura virus by electron microscopy, complement fixation, and neutralisation tests. Chandipura virus RNA was detected in clinical samples from nine patients. Sequencing of five of these RNA samples showed 96.7-97.5% identity with the reference strain of 1965. Chandipura viral antigen and RNA were detected in brain tissue of a deceased child by immunofluorescent antibody test and PCR. Neutralising, IgG, and IgM antibodies to Chandipura virus were present in some patients' serum samples. Serum samples obtained after 4 days of illness were more frequently positive for IgM to Chandipura virus than were those obtained earlier (p<0.001). A similar trend was noted for neutralising antibodies. INTERPRETATION: Our findings suggest that this outbreak of acute encephalitis in Andhra Pradesh was associated with Chandipura virus, adding to the evidence suggesting that this virus should be considered as an important emerging pathogen.
Subject(s)
Disease Outbreaks , Encephalitis, Viral/epidemiology , Rhabdoviridae Infections/epidemiology , Vesiculovirus , Acute Disease , Adolescent , Antibodies, Viral/blood , Brain/virology , Child , Child, Preschool , Communicable Diseases, Emerging , Encephalitis, Viral/diagnosis , Encephalitis, Viral/mortality , Encephalitis, Viral/virology , Enzyme-Linked Immunosorbent Assay , Female , Humans , India/epidemiology , Infant , Male , Polymerase Chain Reaction , Rhabdoviridae Infections/diagnosis , Rhabdoviridae Infections/mortality , Serologic Tests , Survival Rate , Vesiculovirus/isolation & purificationABSTRACT
Leptospirosis is a disease with protean manifestations. We report a case of Guillain-Barre syndrome (GBS) in a pediatric patient following infection with Leptospira. Infecting Leptospira presumably belonged to serovar Copenhageni. The patient recovered completely. The possibility of GBS developing as a result of antecedent leptospiral infection should be kept in mind.
