Clinical, epidemiological, and molecular investigation of Kyasanur forest disease from Karnataka state, India during 2018-2019.

BACKGROUND: In this study, we carried out an investigation of Kyasanur Forest Disease (KFD) suspected human cases reported in Karnataka state, India from December 2018 to June 2019. METHODS: The clinical samples of KFD suspected cases (n = 1955) from 14 districts of Karnataka were tested for KFD using real-time RT-PCR and IgM ELISA. Further, the KFD-negative samples were tested for IgM antibodies against dengue and chikungunya viruses. Monkey samples (n = 276) and tick pools (n = 11582) were also screened using real-time RT-PCR. KFD-positive samples were further analysed using next-generation sequencing along with clinico-epidemiological analysis. RESULTS: Of all, 173 (8.8%) cases tested positive for KFD either by real-time RT-PCR (n = 124), IgM ELISA (n = 53) or both tests (n = 4) from seven districts. Among KFD-negative cases, IgM antibody positivity was observed for dengue (2.6%), chikungunya (5.8%), dengue and chikungunya coinfection (3.7%). KFD cases peaked in January 2019 with fever, conjunctivitis, and myalgia as the predominant symptoms and a mortality of 4.6%. Among confirmed cases, 41% received a single dose and 20% received two doses of the KFD vaccine. Of the seven districts with KFDV positivity, Shivamogga and Hassan districts reported KFD viral RNA positivity in humans, monkeys, and ticks. Sequencing analysis of 2019 cases demonstrated a difference of less than 1.5% amino acid compared to prototype KFDV. CONCLUSION: Although the KFD has been endemic in many districts of Karnataka state, our study confirms the presence of KFDV for the first time in two new districts, i.e. Hassan and Mysore. A comparative analysis of KFDV infection among the KFD-vaccinated and non-vaccinated populations demonstrated an insignificant difference.

Simplified visual detection of Kyasanur Forest Disease virus employing Reverse Transcriptase-Polymerase Spiral Reaction (RT-PSR).

Among recently prevalent tick-borne infections in India, Kyasanur Forest Virus Disease (KFD) is an important public health concern. During last decade the emergence of cases apart from endemic zone raised concern about case positivity. Early diagnosis is therefore very important in disease management and primary containment. This study, aimed to develop a simplified viral RNA extraction in combination to dry down format of novel isothermal assay for (Reverse Transcription- Polymerase Spiral reaction) specific and rapid identification of Kyasanur Forest Disease Virus targeting viral envelope gene. The one step method was optimized by magnetic bead based viral RNA extraction followed by isothermal RT-PSR assay in heat bath at 63°C for 60 minutes. Further, visual results interpretation was done by color change of Hydroxy Naphthol Blue dye. The detection limit of the assay was found 10 RNA copies/rxn with comparable to silica column based viral RNA combined real time qPCR. No cross reactivity was observed with other closely related flaviviruses. The assay was evaluated with clinical samples has shown >99% concordance between two methods. This is the first report of sample extraction coupled isothermal detection of KFD in a simplified manner without a need of any hi-end equipment. The assay developed here has potential to use as an alternate for field-based detection in resource limited settings for KFD.

Development and application of a recombinant Envelope Domain III protein based indirect human IgM ELISA for Kyasanur forest disease virus.

Kyasanur forest virus disease (KFD) is a major public health concern in India. Its etiology KFD virus causes haemorrhagic fever with severe sequelae in humans. Due to continuous spatiotemporal expansion of KFD in last decade, the incidences of positive cases have been increasing in both humans and primates. Early diagnosis is of prime importance for disease management and epidemiological containment. In the present study, the highly immunogenic Envelope Domain III (EDIII) antigen was produced using prokaryotic expression system with an yield of 8 mg/L. The protein was purified using affinity chromatography and confirmed for its immuno-reactivity by western blot and UPLCMS/MS analysis. The recombinant EDIII was used as an antigen for the standardization of ELISA to detect anti KFD IgM antibodies in humans. The ROC curve was prepared to set the optimum cut-off OD for the assay. The comparative evaluation of the assay with a reference MAC ELISA revealed 86.96% concordance, 82.22% sensitivity and 91.48% specificity. Inter-rater agreement was performed with kappa index revealing significant agreement between the assays. This is the first study using safe recombinant protein antigen-based detection of anti KFDV antibodies in humans. This simple and scalable ELISA assay will be applicable for large scale screening of samples for combating the emerging threats of KFD in newer territories.

Kinetics of human infection with Kyasanur Forest Disease Virus.

BACKGROUND: Kyasanur Forest disease (KFD) was first reported in 1957 and became an emerging tick-borne viral disease of public health importance in India. However, very little is known about the host-virus interaction and pathogenesis of KFD in humans. This study described the presence, duration, and kinetics of KFDV RNA in body fluids in infected human cases. METHODOLOGY: We enrolled 76 laboratory-confirmed KFD individuals and followed them up in the study. We obtained serial samples of blood, throat swabs in viral transport medium (VTM), urine, stool, and semen during the acute and convalescent phase of KFD illness. In addition, specimens were inactivated, and nucleic acid was extracted and tested for KFDV real-time reverse transcriptase -PCR. Clinical data was also obtained from the subjects. RESULT: The study provides evidence of KFD virus RNA in different biological body fluids of humans. The percentage positivity of KFDV RNA in blood was 100% during the first four days of illness. PCR became negative in most cases by 7-8 days; a subset of cases (14%) had prolonged viremia for up to 15 days post-onset of illness. Relatively low copies of KFDV RNA were also detected in throat swabs and urine in the first week of illness. In addition, we detected KFDV RNA in stool samples of cases of those who had diarrhea at an early stage of infection. CONCLUSION: The study provides evidence of KFDV RNA in different biological body fluids, which will help understand the pathogenesis, transmission pattern and develop diagnostic algorithms of KFDV in humans. In Kyasanur Forest disease infection, the blood has more RNA copies/ml than other body fluids, and viremia may last up to two weeks post-infection.

Kyasanur forest disease: a state-of-the-art review.

Kyasanur forest disease (KFD) virus is a flavivirus that can be transmitted to humans from monkeys or other mammals through hard ticks (Haemaphysalis spinigera). The disease is endemic to 16 districts in 5 states of Southern India and is reported in the dry season, most commonly in humans travelling to the forests in these areas. The aim of this systematic review is to raise awareness of the clinical and laboratory manifestation of KFD among physicians and travel medicine practitioners. A total of 153 articles were screened of which 16 articles that met the inclusion and exclusion criteria were included for qualitative analysis. KFD is an acute haemorrhagic fever with a biphasic component in some individuals. The second phase is usually marked by neurological symptoms. Leucopoenia, thrombocytopenia and elevated transaminases are the hallmarks of the first phase of KFD. The diagnostic modality of choice in the first few days of illness is polymerase chain reaction assay, whereas serology is used in the late phase. In the absence of a specific antiviral treatment, the clinical management of patients is limited to supportive care. Avoidance of exposure and vaccination is recommended to prevent this infection.

Kyasanur Forest Disease, is our surveillance system healthy to prevent a larger outbreak? A mixed-method study, Shivamogga, Karnataka, India: 2019.

BACKGROUND: Kyasanur Forest disease (KFD) is a tick-borne zoonosis that is endemic in Karnataka. Against the backdrop of the recent geographical expansion of KFD, indicating the inadequacy of policy and surveillance systems, the present study was performed to evaluate the KFD surveillance system in Shivamogga. METHODS: US Centers for Disease Control and Prevention guidelines for surveillance system evaluation were followed. Nine attributes of the system towards its objectives were evaluated in a mixed study in Shivamogga. RESULTS: Two of three medical officers and four of six health staff at the institutions visited were found to be untrained in KFD surveillance. Integrated disease surveillance formats did not capture KFD data. Surveillance (tick, monkey, human) was mostly driven by the Health Department. Some of the critical findings of the evaluations were the absence of an animal and entomological surveillance line list, non-standardized reporting formats for human suspects, varying delays in the time-to-test across laboratories (2-16 days), and a lack of systematic data-sharing practices. Significant issues that emerged in the interview were deforestation with a change in ecosystem dynamics, limited diagnostic capacity, non-availability of point-of-care tests, outdated surveillance guidelines, a confusing surveillance perimeter (5 km), non-existing co-ownership among stakeholders, limited vaccine production capacity, and inadequate operational research. CONCLUSIONS: The system should consider integrating a One Health approach with defined ownership of activities among stakeholders. Revision of the guidelines is mandatory.

Point of care real-time polymerase chain reaction-based diagnostic for Kyasanur forest disease.

OBJECTIVES: Due to the remote forest area locations of sporadic cases and outbreaks of Kyasanur forest disease (KFD), rapid diagnosis poses a significant challenge. This study aimed to evaluate the diagnostic performance of Truenat KFD, a simple, rapid and user-friendly point-of-care test for detection of KFD and compare diagnostic accuracy with conventional real-time reverse transcription-polymerase chain reaction (RT-PCR) testing. Truenat KFD can be deployed in a field laboratory setting. METHODS: The study involved 145 clinical specimens, including human serum, monkey necropsy tissues and tick pool, to validate Truenat KFD (Molbio Diagnostics Pvt.Ltd.) for KFD diagnosis. RESULTS: We have optimized and validated the microchip-based Truenat KFD (Molbio Diagnostics Pvt.Ltd.) for KFD diagnosis. Point-of-care testing was highly sensitive and specific, with a detection limit of up to 10 copies of KFD viral RNA. Results were comparable with the gold-standard TaqMan and commercially available Altona RealStar AHFV / KFDV real-time RT-PCR assays. Screening results for human, monkey and tick specimens were 100% concordant across the assays. CONCLUSION: Truenat KFD(Molbio Diagnostics Pvt.Ltd.) was found to be highly sensitive and specific with a significant limit of detection. This point-of-care test would be useful in rapid diagnosis of KFD in remote and/or field settings, quick patient management and control of virus spread.

Difference in clinical presentation between the first and second phases of Kyasanur Forest disease: an experience from a teaching hospital in South India.

Kyasanur forest disease (KFD) is a biphasic tick-borne disease which occurs during the post-monsoon season. The patient may visit the hospital in either of the phases, and it is essential to differentiate between the two phases as the management considerations in both phases are different. This is a retrospective review of patients diagnosed with KFD who were treated by the Infectious Disease Department between September 2019 and May 2020. A total of 14 cases (16 admissions) were diagnosed during the study period by reverse-transcriptase polymerase chain reaction assay. Of these, nine cases came to our hospital during the first phase and seven (including two-readmissions) came to our hospital during the second phase. The manifestations in the first phase included high-grade fever (100%), myalgia (67%), conjunctival suffusion (33%), palatal eruptions (78%), gastrointestinal manifestations (67%), leucopenia (100%), thrombocytopenia (89%), elevated transaminases (89%), elevated creatine phosphokinase (100%) and activated partial thromboplastin time (APTT) (100%). Manifestations in the second phase were fever (57%), headache (100%), blurring of vision (29%), neck signs (71%), leukocytosis (71%), thrombocytopenia (14%), elevated transaminases (40%) and APTT (20%). The clinical symptomatology and laboratory manifestations are different in each of the two phases and can be easily identified by primary care physicians.

Kyasanur Forest Disease Classification Framework Using Novel Extremal Optimization Tuned Neural Network in Fog Computing Environment.

Kyasanur Forest Disease (KFD) is a life-threatening tick-borne viral infectious disease endemic to South Asia and has been taking so many lives every year in the past decade. But recently, this disease has been witnessed in other regions to a large extent and can become an epidemic very soon. In this paper, a new fog computing based e-Healthcare framework has been proposed to monitor the KFD infected patients in an early phase of infection and control the disease outbreak. For ensuring high prediction rate, a novel Extremal Optimization tuned Neural Network (EO-NN) classification algorithm has been developed using hybridization of the extremal optimization with the feed-forward neural network. Additionally, a location based alert system has also been suggested to provide the global positioning system (GPS)-based location information of each KFD infected user and the risk-prone zones as early as possible to prevent the outbreak. Furthermore, a comparative study of proposed EO-NN with state of art classification algorithms has been carried out and it can be concluded that EO-NN outperforms others with an average accuracy of 91.56%, a sensitivity of 91.53% and a specificity of 97.13% respectively in classification and accurate identification of risk-prone areas.

Epidemiology, Pathogenesis, and Control of a Tick-Borne Disease- Kyasanur Forest Disease: Current Status and Future Directions.

In South Asia, Haemaphysalis spinigera tick transmits Kyasanur Forest Disease Virus (KFDV), a flavivirus that causes severe hemorrhagic fever with neurological manifestations such as mental disturbances, severe headache, tremors, and vision deficits in infected human beings with a fatality rate of 3-10%. The disease was first reported in March 1957 from Kyasanur forest of Karnataka (India) from sick and dying monkeys. Since then, between 400 and 500 humans cases per year have been recorded; monkeys and small mammals are common hosts of this virus. KFDV can cause epizootics with high fatality in primates and is a level-4 virus according to the international biosafety rules. The density of tick vectors in a given year correlates with the incidence of human disease. The virus is a positive strand RNA virus and its genome was discovered to code for one polyprotein that is cleaved post-translationally into 3 structural proteins (Capsid protein, Envelope Glycoprotein M and Envelope Glycoprotein E) and 7 non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5). KFDV has a high degree of sequence homology with most members of the TBEV serocomplex. Alkhurma virus is a KFDV variant sharing a sequence similarity of 97%. KFDV is classified as a NIAID Category C priority pathogen due to its extreme pathogenicity and lack of US FDA approved vaccines and therapeutics; also, the infectious dose is currently unknown for KFD. In India, formalin-inactivated KFDV vaccine produced in chick embryo fibroblast is being used. Nevertheless, further efforts are required to enhance its long-term efficacy. KFDV remains an understudied virus and there remains a lack of insight into its pathogenesis; moreover, specific treatment to the disease is not available to date. Environmental and climatic factors involved in disseminating Kyasanur Forest Disease are required to be fully explored. There should be a mapping of endemic areas and cross-border veterinary surveillance needs to be developed in high-risk regions. The involvement of both animal and health sector is pivotal for circumscribing the spread of this disease to new areas.

Occupational exposure of cashew nut workers to Kyasanur Forest disease in Goa, India.

A series of suspected cases of Kyasanur Forest disease (KFD) in subjects returning to Belgaum in Karnataka State from Goa, India, is reported herein. KFD was confirmed in 13 out of 76 cases, either by real time RT-PCR or IgM ELISA. No case fatality was recorded. KFD virus positivity was also recorded among humans and monkeys from Sattari taluk in Goa during the same period. The envelope gene sequence of positive human samples from Belgaum showed highest identity of 99.98% to 99.99% with sequences of KFD virus isolated from human cases and monkeys from Goa. KFD activity has been reported from Goa among humans and monkeys since 2015. However, it has not been reported from Belgaum to date. These findings suggest that the cases (migrant laborers) contracted infection during cashew nut harvesting from KFD-affected Keri village, Sattari taluk, Goa and became ill after or during migration from the affected area to their native residence.

Kyasanur Forest Disease - First Reported Case in Kerala.

Kyasanur Forest disease is a tick-borne arboviral fever with biphasic course of illness with prominent hemorrhagic features in the first phase and encephalitic picture in the second phase. So far it has been described in the southern Karnataka only. Here we report a case of Kyasanur Forest Disease for the first time from Kerala in an 18 year old male from Noolpuzha - Alathoor colony of Wayanad district.

Diagnosis of Kyasanur forest disease by nested RT-PCR, real-time RT-PCR and IgM capture ELISA.

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.

Alkhurma hemorrhagic fever in travelers returning from Egypt, 2010.

Two travelers returning to Italy from southern Egypt were hospitalized with a fever of unknown origin. Test results showed infection with Alkhurma virus. The geographic distribution of this virus could be broader than previously thought.