Risk of infection with arboviruses in a healthy population in Pakistan based on seroprevalence.

Infectious diseases caused by arboviruses are a public health concern in Pakistan. However, the studies on data prevalence and threats posed by arboviruses are limited. This study investigated the seroprevalence of arboviruses in a healthy population in Pakistan, including severe fever with thrombocytopenia syndrome virus (SFTSV), Crimean-Congo haemorrhagic fever virus (CCHFV), Tamdy virus (TAMV), and Karshi virus (KSIV) based on a newly established luciferase immunoprecipitation system (LIPS) assays, and Zika virus (ZIKV) by enzyme-linked immunosorbent assays (ELISA). Neutralizing activities against these arboviruses were further examined from the antibody positive samples. The results showed that the seroprevalence of SFTSV, CCHFV, TAMV, KSIV, and ZIKV was 17.37%, 7.58%, 4.41%, 1.10%, and 6.48%, respectively, and neutralizing to SFTSV (1.79%), CCHFV (2.62%), and ZIKV (0.69%) were identified, as well as to the SFTSV-related Guertu virus (GTV, 0.83%). Risk factors associated with the incidence of exposure and levels of antibody response were analysed. Moreover, co-exposure to different arboviruses was demonstrated, as thirty-seven individuals were having antibodies to multiple viruses and thirteen showed neutralizing activity. Males, individuals aged ≤ 40 years, and outdoor workers had high risk of exposure to arboviruses. All these results reveal the substantial risks of infection with arboviruses in Pakistan, and indicate the threat from co-exposure to multiple arboviruses. The findings raise the need for further epidemiologic investigation in expanded regions and populations and the necessity to improve health surveillance in Pakistan.

Serologic Evidence of Severe Fever with Thrombocytopenia Syndrome Virus and Related Viruses in Pakistan.

We describe the seroprevalence of severe fever with thrombocytopenia syndrome virus (SFTSV) and the association of antibody occurrence with location, sex, and age among the human population in Pakistan. Our results indicate substantial activity of SFTSV and SFTSV-related viruses in this country.

Crimean-Congo Hemorrhagic Fever Virus in Humans and Livestock, Pakistan, 2015-2017.

We detected Crimean-Congo hemorrhagic fever virus infections in 4 provinces of Pakistan during 2017-2018. Overall, seroprevalence was 2.7% in humans and 36.2% in domestic livestock. Antibody prevalence in humans was highest in rural areas, where increased contact with animals is likely.

Detection of West Nile virus lineage 1 sequences in blood donors, Punjab Province, Pakistan.

OBJECTIVES: This study was performed to determine the presence of West Nile virus (WNV) in mosquito specimens and human blood donors in Pakistan. METHODS: A total of 4150 mosquito specimens were collected using CO2-baited traps from five selected districts of Punjab Province, Pakistan. The mosquitoes were taxonomically identified using standard morphological keys, resulting in 166 pools. In addition, 1070 serum samples were collected from human blood donors. RNA was extracted from mosquito and human samples and screened for WNV using a reverse transcriptase PCR (RT-PCR). RESULTS: None of the mosquito pools tested positive for WNV, whereas three samples from asymptomatic humans tested positive. To determine the WNV strains, partial sequences were compared against a global representation of 23 WNV sequences. The study strains were determined to come from WNV lineage 1. CONCLUSIONS: This study is novel in reporting the circulation of lineage 1 WNV in Pakistan. Given its ability to transmit from human to human via blood transfusion, this highlights the urgent need for nationwide surveillance to assess the distribution and impact of WNV in Pakistan. Determining the source of human infection will require more extensive mosquito sampling.

Countrywide Survey for MERS-Coronavirus Antibodies in Dromedaries and Humans in Pakistan.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a zoonotic pathogen capable of causing severe respiratory disease in humans. Although dromedary camels are considered as a major reservoir host, the MERS-CoV infection dynamics in camels are not fully understood. Through surveillance in Pakistan, nasal (n = 776) and serum (n = 1050) samples were collected from camels between November 2015 and February 2018. Samples were collected from animal markets, free-roaming herds and abattoirs. An in-house ELISA was developed to detect IgG against MERS-CoV. A total of 794 camels were found seropositive for MERS-CoV. Prevalence increased with the age and the highest seroprevalence was recorded in camels aged > 10 years (81.37%) followed by those aged 3.1-10 years (78.65%) and ≤ 3 years (58.19%). Higher prevalence was observed in female (78.13%) as compared to male (70.70%). Of the camel nasal swabs, 22 were found to be positive by RT-qPCR though with high Ct values. Moreover, 2,409 human serum samples were also collected from four provinces of Pakistan during 2016-2017. Among the sampled population, 840 humans were camel herders. Although we found a high rate of MERS-CoV antibody positive dromedaries (75.62%) in Pakistan, no neutralizing antibodies were detected in humans with and without contact to camels.

Seroprevalence and Risk Factors for Theileria equi Infection in Equines from Khyber Pakhtunkhwa Province, Pakistan.

BACKGROUND: Theileria equi is a tick borne protozoan parasite which causes piroplasmosis among equines worldwide. The present study was aimed to determine seroprevalence of T. equi in donkeys, horses, and mules from two equine populated districts (Peshawar and Charsadda) of Khyber Pakhtunkhwa (KPK), Pakistan. METHODS: A total of 393 equine (195 horses, 194 donkeys and 4 mules) serum samples were collected from five and four randomly selected localities in Charsadda (n = 193) and Peshawar (n = 200), respectively. The presence of antibodies to T. equi was determined using a commercially available competitive enzyme-linked immunosorbent assay. RESULTS: An overall seroprevalence of 38.2% (n=150) was observed among all the tested animals suggesting a higher seropositivity among equids belonging to Charsada (50.3%) as compared to Peshawar (27.5%). Binary logistic regression analysis revealed that being a donkey (OR 2.94), having tick infestation (OR 4.32), history of voiding red (i.e., blood containing) urine (OR 3.97) and anemia (OR 2.1) were the factors significantly associated with the seroprevalence of T. equi. For animals with higher anti-T. equi antibody titers, a strong association of seroprevalence for T. equi was recorded with species, age, sex, tick infestation, anemia and history of hematuria. CONCLUSION: The present study indicates a high level of exposure of working equids to T. equi in KPK region, Pakistan. Future studies should focus on tick vector identification and other factors responsible for spread of the disease.