Cross-sectional Serosurvey of Crimean-Congo Hemorrhagic Fever Virus IgG in Livestock, India, 2013-2014

Crimean-Congo hemorrhagic fever virus prevalence in livestock of Jabalpur, Madhya Pradesh, Central India and its implications for public health

The rise of Crimean-Congo Hemorrhagic Fever (CCHF), poses a significant global health challenge, urging immediate action and continuous surveillance. With no available vaccines, monitoring pathogen presence is critical to identify at-risk areas promptly. A study was designed to assess the incidence of CCHF virus in goats and cattle using commercial ELISA IgG kits in tribal-dominated regions. Overall, 16% of the samples (n = 63/393) were positive for CCHF virus-specific IgG antibodies, whereas sero-prevalence detected in cattle 11.6% [95% CI:7-17.7] and in goats 18.9% [95% CI: 13.76-24.01], respectively. Statistically, Animal gender and age didn't significantly affect prevalence (p-value >0.05). Our finding indicates unnoticed CCHF virus circulation. Notably, lack of public awareness about zoonotic diseases in the study region was recorded. To combat this emerging tick-borne disease effectively, it's crucial to screen individuals with hemorrhagic manifestations in healthcare settings and active surveillance of ticks to prevent unwarranted public health outbreaks and design preventive interventions.

Study on the Ixodid ticks species diversity (Acari: Ixodidae) on domestic ruminants in different agro-climatic regions of Tamil Nadu

A survey of Ixodid tick species diversity on domestic ruminants was conducted in seven agro-climatic regions of Tamil Nadu State, India. Tick surveys were conducted on domestic ruminants such as cattle, buffalo, sheep, and goat in seven districts of Tamil Nadu. The overall tick infestation was 38.8%, 5.8%, 14.6%, and 40.8% on cattle, buffaloes, sheep, and goats, respectively. A total of 8068 ticks from 18 species belonging to four genera were recorded. Overall, Haemaphysalis intermedia was the predominant (51.38%) tick species which has a wide host range. The most prevalent tick species in cattle and buffalo were Rhipicephalus (B.) microplus (25.41%) and Rhipicephalus haemaphysaloides (56.69%), respectively. Haemaphysalis intermedia was the most prevalent in ticks in sheep (70.35%), goat (70.35%), and dog (55.79%). In the present study, local anomalies such as the ectromely of one leg and the absence of adanal plates were observed in Rh. haemaphysaloides. The study also found that local anomaly such as protuberances in the hind tarsal and atrophy of the adanal plate was observed in Rhipicephalus (Boophilus) microplus. In addition, a general anomaly with three atrophy caudal appendages was also observed in Rhipicephalus (Boophilus) microplus. The overall prevalence of anomalies in Rh. haemaphysaloides and Rh. (B.) microplus was 0.3% (3/971) and 0.4% (3/678), respectively.

Quantifying the influence of climate, host and change in land-use patterns on occurrence of Crimean Congo Hemorrhagic Fever (CCHF) and development of spatial risk map for India

Crimean Congo Hemorrhagic Fever (CCHF), is an emerging zoonosis globally and in India. The present study focused on identifying the risk factors for occurrence of CCHF in the Indian state of Gujarat and development of risk map for India. The past CCHF outbreaks in India were collated for the analyses. Influence of land use change and climatic factors in determining the occurrence of CCHF in Gujarat was assessed using Bayesian spatial models. Change in maximum temperature in affected districts was analysed to identify the significant change points over 110 years. Risk map was developed for Gujarat using Bayesian Additive Regression Trees (BART) model with remotely sensed environmental variables and host (livestock and human) factors. We found the change in land use patterns and maximum temperature in affected districts to be contributing to the occurrence of CCHF in Gujarat. Spatial risk map developed using CCHF occurrence data for Gujarat identified density of buffalo, minimum land surface temperature and elevation as risk determinants. Further, spatial risk map for the occurrence of CCHF in India was developed using selected variables. Overall, we found that combination of factors such as change in land-use patterns, maximum temperature, buffalo density, day time minimum land surface temperature and elevation led to the emergence and further spread of the disease in India. Mitigation measures for CCHF in India could be designed considering disease epidemiology and initiation of surveillance strategies based on the risk map developed in this study.

Situation Analysis and Recommendations for the Biosecurity Status of Dairy Farms in Punjab, India: A Cross-Sectional Survey

Farm biosecurity is an important herd management strategy to assure infection prevention and animal health. The present study aimed to evaluate the implementation of biosecurity measures on dairy farms in Punjab, India, using the standardized Biocheck.UGent™ scoring system. Convenience sampling was used to select 94 dairy farms, comprising both cattle and buffaloes, with a mean herd size of 74.8 animals. The study found that the mean external and internal biosecurity scores for the selected dairy farms were 45.4% and 43.7%, respectively. Among the subcategories, the highest external biosecurity score was observed for 'vermin control and other animals' (63%), and the highest internal biosecurity score was observed for 'adult cattle management' (76.6%). Whereas the lowest score for external biosecurity was observed for 'purchase and reproduction' (30.6%), and the lowest score for internal biosecurity was observed for 'health management' (33.6%). The overall mean biosecurity score of the present study was 44.8%, which was lower than the overall mean global score of 52%. The correlation analysis indicated a positive correlation between herd size and overall biosecurity scores, indicating that larger farms had, on average, higher biosecurity scores. Based on these results, it can be concluded that the implementation of biosecurity measures on dairy farms in Punjab needs improvement, especially in the subcategories of 'purchase and reproduction' and 'health management'. Further research to identify the factors influencing the implementation of biosecurity measures on dairy farms in the region is recommended.

Assessing and Prioritizing Zoonotic Diseases in Punjab, India: A One Health Approach

Zoonotic diseases have a significant impact on both human and animal health globally. The present study was planned to prioritize the zoonoses in Punjab state of India. To develop a zoonotic disease prioritization scoring system, a comprehensive approach has been taken, including literature review, key person interviews with animal health experts (n = 12) and medical professionals (n = 7), and nine focus group discussions (FGDs) with veterinary academicians, medical professionals, and field veterinary doctors. The scoring system comprises of seven major criteria, each assigned a weightage score (ws): prevalence/incidence of the disease (ws = 0.20), severity of illnesses in humans (ws = 0.18), epidemic potential (ws = 0.16), socio-economic burden (ws = 0.16), availability of effective control and prevention measures (ws = 0.15), inter-sectoral collaborations (ws = 0.1), and bioterrorism potential (ws = 0.05). The finalized scoring system, accompanied by a list of 15 selected zoonotic diseases, was implemented among a group of 23 professionals engaged in zoonoses research (n = 7), animal health (n = 10), and medical health (n = 6) to determine their prioritization. The zoonotic diseases prioritized for the Punjab (India) included, Brucellosis (0.70) > Rabies (0.69) > Anthrax (0.64) > Leptospirosis (0.62) = Toxoplasmosis (0.62) = Highly Pathogenic Avian Influenza (HPAI) (0.62) > Bovine tuberculosis (0.61) > Q fever (0.60) > Cysticercosis (0.59) > Listeriosis (0.58) > Crimean-Congo haemorrhagic fever (CCHF) (0.57) > Japanese encephalitis (0.56) = Echinococcosis (0.56) > Dermatophytosis (0.53) > and Scrub typhus (0.48), respectively. Higher priority is suggested for endemic zoonoses (e.g., brucellosis and rabies) as compared to those with epidemic potential (e.g., CCHF, HPAI etc.) in Punjab. Results of the current study will help in the development of targeted control and prevention strategies for zoonotic diseases in Punjab and other geographical regions facing similar challenges.

Development of anti-Crimean-Congo hemorrhagic fever virus Gc and NP-specific ELISA for detection of antibodies in domestic animal sera

Crimean-Congo hemorrhagic fever (CCHF) is a priority emerging disease. CCHF, caused by the CCHF virus (CCHFV), can lead to hemorrhagic fever in humans with severe cases often having fatal outcomes. CCHFV is maintained within a tick-vertebrate-tick cycle, which includes domestic animals. Domestic animals infected with CCHFV do not show clinical signs of the disease and the presence of antibodies in the serum can provide evidence of their exposure to the virus. Current serological tests are specific to either one CCHFV antigen or the whole virus antigen. Here, we present the development of two in-house ELISAs for the detection of serum IgG that is specific for two different CCHFV antigens: glycoprotein Gc (CCHFV Gc) and nucleoprotein (CCHFV NP). We demonstrate that these two assays were able to detect anti-CCHFV Gc-specific and anti-CCHFV NP-specific IgG in sheep from endemic CCHFV areas with high specificity, providing new insight into the heterogeneity of the immune response induced by natural infection with CCHFV in domestic animals.

Prevalence of Crimean-Congo Hemorrhagic Fever Virus among Livestock and Ticks in Zhambyl Region, Kazakhstan, 2017

Crimean-Congo hemorrhagic fever (CCHF) is a highly fatal zoonotic disease endemic to Kazakhstan. Previous work estimated the seroprevalence of CCHF virus (CCHFV) among livestock owners in the Zhambyl region of southern Kazakhstan at 1.2%. To estimate CCHFV seroprevalence among cattle and sheep, we selected 15 villages with known history of CCHFV circulation (endemic) and 15 villages without known circulation (nonendemic) by cluster sampling with probability proportional to livestock population size. We collected whole blood samples from 521 sheep and 454 cattle from randomly selected households within each village and collected ticks found on the animals. We tested livestock blood for CCHFV-specific IgG antibodies by ELISA; ticks were screened for CCHFV RNA by real-time reverse transcription polymerase chain reaction and CCHFV antigen by antigen-capture ELISA. We administered questionnaires covering animal demographics and livestock herd characteristics to an adult in each selected household. Overall weighted seroprevalence was 5.7% (95% CI: 3.1, 10.3) among sheep and 22.5% (95% CI: 15.8, 31.2) among cattle. CCHFV-positive tick pools were found on two sheep (2.4%, 95% CI: 0.6, 9.5) and three cattle (3.8%, 95% CI: 1.2, 11.5); three CCHFV-positive tick pools were found in nonendemic villages. Endemic villages reported higher seroprevalence among sheep (15.5% versus 2.8%, P < 0.001) but not cattle (25.9% versus 20.1%, P = 0.42). Findings suggest that the current village classification scheme may not reflect the geographic distribution of CCHFV in Zhambyl and underscore that public health measures must address the risk of CCHF even in areas without a known history of circulation.

A study on viral haemorrhagic fever due to dengue, chikungunya and Crimean Congo haemorrhagic fever virus among patients attending tertiary care hospital in North East India

PURPOSE

The present study was undertaken with the objective to study the common etiology of Viral Haemorrhagic Fever (VHF) among patients attending tertiary health care centre in NE India and also to study the clinico-demographic profile of such patients. The agents of VHF included in the study were dengue, chikungunya and Crimean Congo haemorrhagic fever (CCHF) virus. The inclusion of CCHF was based on evidence of seroprevalence in livestock (bovine, sheep and goat) in various North Eastern states.

MATERIALS AND METHODS

Serum samples were collected from 51 suspected VHF patients. MAC-ELISA was done to detect dengue and chikungunya specific IgM antibody. The samples were also tested by real-time RT-PCR for detection of dengue, chikungunya and CCHF specific nucleic acid. The laboratory and clinico-demographic profile of these patients were noted in detail.

RESULTS

Serum samples of 16 of 51 suspected cases were confirmed to be suffering from VHF. Among these confirmed cases, 12 were diagnosed with dengue haemorrhagic fever, one was diagnosed with chikungunya and three were diagnosed with dengue-chikungunya co-infection. Based on severity, DHF was further classified into- DHF I- (4,26.6%), DHF II (6,40%), DHF III (3,20%) and DHF IV (2,13.3%). There was no CCHFV infection detected in our study. Retro-orbital pain (P ​= ​0.02) and haematocrit level (P ​= ​0.03) were found to be statistically significant.

CONCLUSIONS

This study reiterates the fact that CCHF virus infection is still probably absent in human population of NE India and haemorrhagic symptoms, though rare maybe one of the atypical manifestations of chikungunya infection.

Experiences of Indian Council of Medical Research with tick-borne zoonotic infections: Kyasanur Forest disease & Crimean-Congo haemorrhagic fever in India with One Health focus

Emergence and re-emergence of several pathogens have been witnessed by this century in the form of outbreaks, epidemics and pandemics. In India, the influencing factor that promotes dissemination of emerging and re-emerging viral infections is the biogeographical zones: a megadiverse country, characterized by varied geographical, climatic conditions and ever-changing socio-economical and geopolitical issues. These influence the movement of humans and animals and add layers of complexity for the identification and timely management of infectious diseases. This review focuses on two tick-borne infections: Crimean-Congo haemorrhagic fever (CCHF) and Kyasanur forest disease (KFD). In the last two decades, these viruses have emerged and caused outbreaks in different parts of India. KFD virus was initially identified in 1957 and was known to be endemic in Karnataka State while CCHF virus was first identified during 2010 in Gujarat State, India. These viruses have managed to emerge in new areas within the last decade. With changing epidemiology of these arboviruses, there is a probability of the emergence of these viruses from new areas in future. The investigations on these two diseases under the One Health focus involved early detection, quickly developing diagnostic tools, identifying stakeholders, capacity building by developing collaboration with major stakeholders to understand the epidemiology and geographical spread in domestic animal reservoirs and tick vectors in the affected areas, developing laboratory network, providing diagnostic reagents and biosafety and laboratory diagnosis training to the network laboratories to control these diseases.

Serological and molecular study of Crimean-Congo Hemorrhagic Fever Virus in cattle from selected districts in Uganda

BACKGROUND

Crimean-Congo Hemorrhagic Fever (CCHF) is a severe tick-borne viral hemorrhagic disease caused by Crimean-Congo Hemorrhagic Fever Virus (CCHFV) that poses serious public health challenges in many parts of Africa, Europe and Asia.

METHODS

We examined 500 cattle sera samples from five districts for CCHFV antibodies using in-house and commercially available (IDVet) ELISA, Immunofluorescent assay (IFA) and Real-time polymerase chain reaction (RT-PCR).

RESULTS

500 cattle (73.8 % females) were analyzed; CCHFV seropositivity was 12.6 % (n = 63) and 75.0 % (n = 375) with the in-house and IDVet ELISAs, respectively. Seropositivity was associated with geographical location, increasing age, being female, and having a higher tick burden. Twenty four out of the 37 (64.8 %) were seropositive for CCHFV using IFA and all were negative for virus on RT-PCR. The IFA results were more comparable to IDVet (κ_coefficient = 0.88, p = <0.01) than to in-house (κ_coefficient = 0.32, p = 0.02).

CONCLUSIONS

Our study confirmed the presence and high prevalence of anti-CCHF antibodies in cattle based on three methods from all the five study districts, confirming presence and exposure of CCHFV. Given the zoonotic potential for CCHFV, we recommend a multidisciplinary public health surveillance and epidemiology of CCHFV in both animals and humans throughout the country.

Detection of African genotype in Hyalomma tick pools during Crimean Congo hemorrhagic fever outbreak, Rajasthan, India, 2019

Crimean Congo hemorrhagic fever (CCHF) is a zoonotic viral disease presenting with fever and hemorrhagic manifestations in humans. After several outbreaks of CCHF being reported from Gujarat since 2011 till 2019 and from Rajasthan in 2014 and 2015, the present study reports the CCHF outbreak which was recorded from five human cases in three districts Jodhpur, Jaisalmer, and Sirohi of Rajasthan state since August 2019 till November 2019. A high percent of positivity was recorded in livestock animal samples for the CCHFV IgG antibody. CCHF virus (CCHFV) positive human blood samples and Hyalomma tick pool samples were sequenced using next-generation sequencing method. Two different M segment genotypes, encoding glycoprotein precursor, were identified from tick pools in the study: first from Asian and second from African lineage. The L gene (polymerase) and the S gene (nucleocapsid) clustered in the Asian lineage. The present study illustrates the existence of two different CCHFV lineages being circulating within the Hyalomma tick pools in the Rajasthan state, India. We also observed 3.56% amino acid changes between the death and the survived case of CCHFV in the M gene. This report also sets an alarm to enhance human, tick and livestock surveillance in other districts of Rajasthan and nearby states of India. Biosafety measures, barrier nursing along with the availability of personal protective equipment and ribavirin drug will always be a mainstay in preventing nosocomial infection for proper case management.

Identification of functional epitopes of structural proteins and in-silico designing of dual acting multiepitope anti-tick vaccine against emerging Crimean-Congo hemorrhagic fever virus

Recurrent outbreaks of Crimean-Congo hemorrhagic fever (CCHF) virus infection in different parts of world are a major global health concern. The CCHF viral infection is associated with severe hemorrhagic fevers and mortality up to 40%. More than 30 countries in Asia, Europe and Africa are affected with CCHF infection. Prevention of infection through vaccine becomes more important when no effective antiviral and associated therapies are available. Further ticks play a crucial role in maintenance and transmission of CCHFV. Therefore, the control of transmission by ticks is warranted for ultimate prevention of outbreak. The study employed a series of immunoinformatics approaches to design novel multiepitope vaccine targeting highly immunodominant epitopes of major structural proteins (Nucleoprotein and Glycoprotein complex) of CCHFV. Vaccine was designed by incorporating linear and conformational B cell, helper and cytotoxic T cell epitopes from these crucial immunogenic proteins adjoined with appropriate linkers and adjuvant. This vaccine construct was also complemented with a highly immunogenic and conserved protective tick salivary antigen named subolesin to impart dual activity as a unique transmission blocking vaccine. The B-cell peptides were also experimentally validated. The designed vaccine was further in silico validated for its physiochemical properties, allergenicity and immunogenicity etc. The proposed candidate vaccine construct has the potential to function both as a vaccine against CCHF virus as well as a universal anti-tick vaccine.

Epidemiological investigations of Crimean-Congo haemorrhagic fever virus infection in sheep and goats in Balochistan, Pakistan

Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne zoonotic disease caused by the arbovirus Crimean-Congo haemorrhagic fever virus (CCHFV). Livestock serve as a transient reservoir for CCHFV, but do not show clinical signs. In this cross-sectional study, sheep and goats in Balochistan, Pakistan, were examined to determine the CCHFV seroprevalence, spatial distribution of seropositive sheep and goats, and to identify potential risk factors for seropositivity to CCHFV in these animals. To this end, farms and animals were selected by systematic sampling, blood samples from 800 sheep and 800 goats were collected and information regarding farm management and the kept animals were retrieved using a standard questionnaire. Sera were tested for antibodies against CCHFV in two independent ELISA formats and an immunofluorescence assay (IFA) following a hierarchical diagnostic decision tree. By these assays 149 (19 %, 95 %-CI: 16-21 %) out of 800 sheep serum samples and 37 (5 %, 95 %-CI: 3-6 %) out of 800 goat serum samples were positive for CCHFV-specific IgG antibodies. Interestingly, at least 8 (5 %, 95 %-CI: 2-10 %) out of 160 sera pools were from CCHFV viraemic sheep, as sera (in pools of 5) tested positive for CCHFV genome by real-time PCR (RT-qPCR). Risk factor analysis revealed that the open type of housing (OR = 3.76, 95 %-CI:1.57-9.56, p-value = 0.003), grazing (OR = 4.18, 95 %-CI:1.79-10.37, p-value = 0.001), presence of vegetation in or around the farm (OR = 3.13, 95 %-CI: 1.07-10.15, p-value = 0.043), lack of treatment against ticks (OR = 3.31, 95 %-CI: 1.16-10.21, p-value = 0.029), absence of rural poultry (OR = 2.93, 95 %-CI: 1.41-6.29, p-value = 0.004), animals with age ≥ 2 years (OR = 4.15, 95 %-CI: 2.84-6.19, p-value<0.001), animals infested with ticks (OR = 2.35, 95 %-CI: 1.59-3.52, p-value<0.001), and sheep species (OR = 4.72, 95 %-CI:3.24-6.86, p-value<0.001) represented statistically significant risk factors associated with seropositivity to CCHFV. Taken together this study confirms the circulation of CCHFV in livestock in Balochistan, Pakistan. The identification of risk factors might help to reduce the risk of infection in sheep and goats, which may also mitigate the risk for human infection. An interesting option for reducing the risk of CCHFV infection in small ruminants is keeping also chickens, since they pick ticks that transmit CCHFV.

Development of Multispecies Recombinant Nucleoprotein-Based Indirect ELISA for High-Throughput Screening of Crimean-Congo Hemorrhagic Fever Virus-Specific Antibodies

Crimean-Congo hemorrhagic fever (CCHF) is a re-emerging zoonotic viral disease prevalent in many parts of Asia, Europe, and Africa. The causative agent, Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV), is transmitted through hard ticks. Tick vectors especially belonging to the Hyalomma species serve as the reservoir and amplifying host. The vertebrate animals including sheep, goat, and bovine act as a short-lasting bridge linking the virus and ticks. CCHFV causes fatal hemorrhagic fever in humans. Humans are usually infected with CCHFV either through the bite of infected ticks or by close contact with infected animals. Immunological assays, primarily enzyme-linked immunosorbent assay (ELISA) using whole viral antigen, are widely used for serosurveillance in animals. However, the whole virus antigen poses a high biohazard risk and can only be produced in biosafety level 4 laboratories. The present study focuses on the development and evaluation of safe, sensitive, and specific IgG indirect enzyme-linked immunosorbent assay (iELISA) using recombinant nucleoprotein (NP) of CCHF virus as an antigen. The codon-optimized NP gene sequence was synthesized, cloned, and expressed in pET28a+ vector. The recombinant NP was purified to homogeneity by affinity chromatography and characterized through Western blot and MALDI-TOF/MS analysis. The characterized protein was used to develop an indirect IgG microplate ELISA using a panel of animal sera. The in-house ELISA was comparatively evaluated vis-à-vis a commercially available ELISA kit (Vector-Best, Russia) with 76 suspected samples that revealed a concordance of 90% with a sensitivity and specificity of 79.4 and 100%, respectively. The precision analysis revealed that the assay is robust and reproducible in different sets of conditions. Further, the assay was used for serosurveillance in ruminants from different regions of India that revealed 18% seropositivity in ruminants, indicating continued circulation of virus in the region. The findings suggest that the developed IgG iELISA employing recombinant NP is a safe and valuable tool for scalable high-throughput screening of CCHFV-specific antibodies in multiple species.

Emerging/re-emerging viral diseases & new viruses on the Indian horizon

Infectious diseases remain as the major causes of human and animal morbidity and mortality leading to significant healthcare expenditure in India. The country has experienced the outbreaks and epidemics of many infectious diseases. However, enormous successes have been obtained against the control of major epidemic diseases, such as malaria, plague, leprosy and cholera, in the past. The country's vast terrains of extreme geo-climatic differences and uneven population distribution present unique patterns of distribution of viral diseases. Dynamic interplays of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. In this article, the major emerging and re-emerging viral infections of public health importance have been reviewed that have already been included in the Integrated Disease Surveillance Programme.

Crimean Congo hemorrhagic fever serosurvey in humans for identifying high-risk populations and high-risk areas in the endemic state of Gujarat, India

Background

Crimean Congo Hemorrhagic Fever (CCHF) is a highly infectious zoonotic disease of humans transmitted by Hyalomma ticks. Earlier studies have shown CCHF seroprevalence in livestock throughout India, yet sporadic outbreaks have been recorded mostly from the Gujarat state of India since 2011. Occupational vulnerability to CCHF for animal handlers, veterinarians, abattoir workers, and healthcare workers has been documented. The current study was planned to determine the seroprevalence of CCHF with an intention to identify the high -risk population and high -risk areas from Gujarat state, India.

Methods

Based on the socio-clinical data, the human population of Gujarat was divided into eight categories viz. A: CCHF affected person/house/close contact, B: Neighborhood contacts, C: Animal handlers, D: General population, E: Farmers, F: Abattoir workers, G: Veterinarian, H: Healthcare workers. A total of 4978 human serum samples were collected from 33 districts of Gujarat during year 2015, 2016 and 2017. All the samples were screened for the presence of anti-CCHFV IgG using indigenously developed anti-CCHFV IgG ELISA. Univariate regression analysis was performed to recognize significant risk factors for CCHF seropositivity.

Results

Twenty-five serum samples were found to be positive with an overall CCHF human seropositivity of 0.5% (95% CI 0.30–0.74%). Gender predisposition to CCHF prevalence was observed in males (OR: 2.80; p-value: 0.020). The risk for seropositivity increased sevenfold when a person was in contact or neighbor with a CCHF case (OR 7.02; p-value: < 0.0001). No significant difference in seropositivity was observed within different age groups. Veterinarians, healthcare workers, and control group were found to be seronegative for CCHF.

Conclusions

In-spite of CCHF sporadic outbreaks reported in Gujarat, the seropositivity for CCHF in the state was low as compared to other endemic countries. Males, close contacts and neighbors were identified as a high-risk population for CCHF infection. To recognize the high-risk area, tick screening and animal serosurvey would be a wiser choice. The study also suggests circulation and under diagnoses of CCHFV in the naïve regions of Gujarat.

Identification and characterization of vaccine candidates against Hyalomma anatolicum-Vector of Crimean-Congo haemorrhagic fever virus

Crimean-Congo haemorrhagic fever (CCHF) is a tick borne viral disease reported from different parts of the world. The distribution of the CCHF cases are linked with the distribution of the principal vector, Hyalomma anatolicum in the ecosystem. Presently, vector control is mainly dependent on repeated application of acaricides, results in partial efficacy and generated acaricide resistant tick strains. Amongst the different components of integrated management programme, immunization of hosts is considered as one of the sustainable component. To restrict CCHF virus spreading, use of anti-Hyalomma vaccines appears as a viable solution. Accordingly, present study was under taken to characterize and evaluate vaccine potential of two conserved molecules, ferritin2 (FER2) and tropomyosin (TPM). Silencing of the genes conferred a cumulative reduction (rejection + unable to engorge) of 61.3% in FER2 and 70.2% in TPM respectively. Furthermore, 44.2% and 72.7% reduction in engorgement weight, 63.6% and 94.9% reduction in egg masses in FER2 and TPM silenced ticks in comparison to LUC-control group was recorded. The recombinant protein, rHaFER2 was characterized as 35 kDa protein with pI of 5.84 and possesses iron binding domains. While rHaTPM is a 51kDa protein with pI of 4.94 having calcium binding domains. Immunization of cross-bred calves by rHaFER2 conferred 51.7% and 51.2% protection against larvae and adults of H. anatolicum challenge infestations. While rHaTPM conferred 63.7% and 66.4% protection against larvae and adults infestations, respectively. The results were comparable with the data generated by RNAi and it clearly showed the possibility for the development of anti-hyalomma vaccine to manage CCHF virus and Theileria annulata infection in human and animals.

Retrospective analysis of clinical information in Crimean-Congo haemorrhagic fever patients: 2014-2015, India

BACKGROUND & OBJECTIVES

Differential diagnosis of Crimean-Congo haemorrhagic fever (CCHF) from other acute febrile illnesses with haemorrhagic manifestation is challenging in India. Nosocomial infection is a significant mode of transmission due to exposure of healthcare workers to blood and body fluids of infected patients. Being a risk group 4 virus, laboratory confirmation of infection is not widely available. In such a situation, early identification of potential CCHF patients would be useful in limiting the spread of the disease. The objective of this study was to retrospectively analyse clinical and laboratory findings of CCHF patients that might be useful in early detection of a CCHF case in limited resource settings.

METHODS

Retrospective analysis of clinical and laboratory data of patients suspected to have CCHF referred for diagnosis from Gujarat and Rajasthan States of India (2014-2015) was done. Samples were tested using CCHF-specific real time reverse transcription (RT)-PCR and IgM ELISA.

RESULTS

Among the 69 patients referred, 21 were laboratory confirmed CCHF cases of whom nine had a history of occupational exposure. No clustering of cases was noted. Platelet count cut-off for detection of positive cases by receiver operating characteristic curve was 21.5×10[9]/l with sensitivity 82.4 per cent and specificity 82.1 per cent. Melaena was a significant clinical presentation in confirmed positive CCHF patients.

INTERPRETATION & CONCLUSIONS

The study findings suggest that in endemic areas thrombocytopenia and melaena may be early indicators of CCHF. Further studies are needed to confirm these findings.

A mini-review of Bunyaviruses recorded in India

Newly emerging and re-emerging viral infections are of major public health concern. Bunyaviridae family of viruses comprises a large group of animal viruses. Clinical symptoms exhibited by persons infected by viruses belonging to this family vary from mild-to-severe diseases i.e., febrile illness, encephalitis, haemorrhagic fever and acute respiratory illness. Several arthropods-borne viruses have been discovered and classified at serological level in India in the past. Some of these are highly pathogenic as the recent emergence and spread of Crimean-Congo haemorrhagic fever virus and presence of antibodies against Hantavirus in humans in India have provided evidences that it may become one of the emerging diseases in this country. For many of the discovered viruses, we still need to study their relevance to human and animal health. Chittoor virus, a variant of Batai virus; Ganjam virus, an Asian variant of Nairobi sheep disease virus; tick-borne viruses such as Bhanja, Palma and mosquito-borne viruses such as Sathuperi, Thimiri, Umbre and Ingwavuma viruses have been identified as the members of this family. As Bunyaviruses are three segmented RNA viruses, they can reassort the segments into genetically distinct viruses in target cells. This ability is believed to play a major role in evolution, pathogenesis and epidemiology of the viruses. Here, we provide a comprehensive overview of discovery, emergence and distribution of Bunyaviruses in India.

Bunyavirales ribonucleoproteins: the viral replication and transcription machinery

The Bunyavirales order is one of the largest groups of segmented negative-sense single-stranded RNA viruses, which includes many pathogenic strains that cause severe human diseases. The RNA segments of the bunyavirus genome are separately encapsidated by multiple copies of nucleoprotein (N), and both termini of each N-encapsidated genomic RNA segment bind to one copy of the viral L polymerase protein. The viral genomic RNA, N and L protein together form the ribonucleoprotein (RNP) complex that constitutes the molecular machinery for viral genome replication and transcription. Recently, breakthroughs have been achieved in understanding the architecture of bunyavirus RNPs with the determination of the atomic structures of the N and L proteins from various members of this order. In this review, we discuss the structures and functions of these bunyavirus RNP components, as well as viral genome replication and transcription mechanisms.

Crimean-Congo Hemorrhagic Fever in Migrant Worker Returning from Oman to India, 2016

In January 2016, a migrant worker who returned home to India after becoming ill in Oman was confirmed to have Crimean-Congo hemorrhagic fever (CCHF). Physicians should include CCHF in the differential diagnosis for patients with hemorrhagic signs and a history of recent travel to any area where CCHF is endemic or prevalent.

Second International Conference on Crimean-Congo Hemorrhagic Fever

The Second International Conference on Crimean-Congo Hemorrhagic Fever (CCHF) was held in Thessaloniki, Greece, from September 10-13, 2017, and brought together international public health professionals, clinicians, ecologists, and basic laboratory researchers. Nearly 100 participants, representing 24 countries and the World Health Organization (WHO), were in attendance. Meeting sessions covered the epidemiology of CCHF in humans; ticks and virus-tick interactions; wild and domestic animal hosts; molecular virology; taxonomic classification; pathogenesis and animal models; clinical aspects and diagnosis; clinical management and clinical trials; and disease prevention in humans. The concluding session focused on recent WHO recommendations for public health measures and future research. This report summarizes lectures by the invited speakers and highlights advances in the field.

Zika virus: Indian perspectives

The emergence of Zika virus (ZiV), a mosquito borne Flavivirus like dengue (DEN) and chikungunya (CHIK), in Brazil in 2014 and its spread to various countries have led to a global health emergency. Aedes aegypti is the major vector for ZiV. Fast dissemination of this virus in different geographical areas posses a major threat especially to regions where the population lacks herd immunity against the ZiV and there is abundance of Aedes mosquitoes. In this review, we focus on current global scenario, epidemiology, biology, diagnostic challenges and remedial measures for ZiVconsidering the Indian perspective.

Nosocomial infection of CCHF among health care workers in Rajasthan, India

BACKGROUND

Ever since Crimean-Congo hemorrhagic fever [CCHF] discovered in India, several outbreaks of this disease have been recorded in Gujarat State, India. During the year 2011 to 2015 several districts of Gujarat and Rajasthan state (Sirohi) found to be affected with CCHF including the positivity among ticks and livestock. During these years many infected individuals succumbed to this disease; which subsequently led to nosocomial infections. Herein, we report CCHF cases recorded from Rajasthan state during January 2015. This has affected four individuals apparently associated with one suspected CCHF case admitted in a private hospital in Jodhpur, Rajasthan.

CASE PRESENTATION

A 30-year-old male was hospitalized in a private hospital in Jodhpur, Rajasthan State, who subsequently had developed thrombocytopenia and showed hemorrhagic manifestations and died in the hospital. Later on, four nursing staff from the same hospital also developed the similar symptoms (Index case and Case A, B, C). Index case succumbed to the disease in the hospital at Jodhpur followed by the death of the case A that was shifted to AIIMS hospital, Delhi due to clinical deterioration. Blood samples of the index case and Case A, B, C were referred to the National institute of Virology, Pune, India for CCHF diagnosis from the different hospitals in Rajasthan, Delhi and Gujarat. However, a sample of deceased suspected CCHF case was not referred. Subsequently, blood samples of 5 nursing staff and 37 contacts (Case D was one of them) from Pokhran area, Jaisalmer district were referred to NIV, Pune.

CONCLUSIONS

It clearly indicated that nursing staff acquired a nosocomial infection while attending the suspected CCHF case in an Intensive Care Unit of a private hospital in Jodhpur. However, one case was confirmed from the Pokhran area where the suspected CCHF case was residing. This case might have got the infection from suspected CCHF case or through other routes. CCHF strain associated with these nosocomial infections shares the highest identity with Afghanistan strain and its recent introduction from Afghanistan cannot be ruled out. However, lack of active surveillance, unawareness among health care workers leads to such nosocomial infections.