Risk factors associated with exposure to Crimean-Congo haemorrhagic fever virus in animal workers and cattle, and molecular detection in ticks, South Africa

Crimean-Congo haemorrhagic fever (CCHF) is a severe tick-borne viral zoonosis endemic to parts of Africa, Europe, the Middle East and Central Asia. Human cases are reported annually in South Africa, with a 25% case fatality rate since the first case was recognized in 1981. We investigated CCHF virus (CCHFV) seroprevalence and risk factors associated with infection in cattle and humans, and the presence of CCHFV in Hyalomma spp. ticks in central South Africa in 2017–18. CCHFV IgG seroprevalence was 74.2% (95%CI: 64.2–82.1%) in 700 cattle and 3.9% (95%CI: 2.6–5.8%) in 541 farm and wildlife workers. No veterinary personnel (117) or abattoir workers (382) were seropositive. The prevalence of CCHFV RNA was significantly higher in Hyalomma truncatum (1.6%) than in H. rufipes (0.2%) (P = 0.002). Seroprevalence in cattle increased with age and was greater in animals on which ticks were found. Seroprevalence in cattle also showed significant geographic variation. Seroprevalence in humans increased with age and was greater in workers who handled livestock for injection and collection of samples. Our findings support previous evidence of widespread high CCHFV seroprevalence in cattle and show significant occupational exposure amongst farm and wildlife workers. Our seroprevalence estimate suggests that CCHFV infections are five times more frequent than the 215 confirmed CCHF cases diagnosed in South Africa in the last four decades (1981–2019). With many cases undiagnosed, the potential seriousness of CCHF in people, and the lack of an effective vaccine or treatment, there is a need to improve public health awareness, prevention and disease control.

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Haemophagocytosis in a patient with Crimean–Congo haemorrhagic fever

Journal of Medical Microbiology ◽

10.1099/jmm.0.46910-0 ◽

2007 ◽

Vol 56 (8) ◽

pp. 1126-1128 ◽

Cited By ~ 15

Author(s):

Atahan Cagatay ◽

Mahir Kapmaz ◽

Asli Karadeniz ◽

Seniha Basaran ◽

Mustafa Yenerel ◽

...

Keyword(s):

Clinical Symptoms ◽

Severe Disease ◽

Case Fatality ◽

Haemorrhagic Fever ◽

Rt Pcr ◽

Patient History ◽

Endemic Region ◽

Cchf Virus ◽

History Of ◽

Crimean Congo Haemorrhagic Fever

Crimean–Congo haemorrhagic fever (CCHF) is a severe disease with a case fatality of 2.8 to 80 %. A patient dwelling in an endemic region for CCHF was admitted with fever preceding bleeding diathesis and pancytopenia. Despite no history of tick exposure, CCHF was highly suspected. With an oral ribavirin therapy, clinical and laboratory improvements were obtained. The diagnosis was confirmed by detection of IgM antibody to CCHF virus and positive RT-PCR. Although the main pathogenesis of CCHF infection is not elucidated yet, haemophagocytosis, a symptom rarely reported in viral haemorrhagic fevers, was observed in this case. Haemophagocytosis is suggested to have a role in the development of pancytopenia in CCHF, the mechanism of which still needs to be investigated, probably with cytokine studies. Together with clinical symptoms and patient history, haemophagocytosis may be an indicator for CCHF.

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Investigation of tick-borne viruses as pathogens of humans in South Africa and evidence of Dugbe virus infection in a patient with prolonged thrombocytopenia

Epidemiology and Infection ◽

10.1017/s0950268800052687 ◽

1996 ◽

Vol 116 (3) ◽

pp. 353-361 ◽

Cited By ~ 46

Author(s):

F. J. Burt ◽

D. C. Spencer ◽

P. A. Leman ◽

B. Patterson ◽

R. Swanepoel

Keyword(s):

South Africa ◽

Febrile Illness ◽

Cross Reactivity ◽

Distribution Range ◽

Antibody Activity ◽

Haemorrhagic Fever ◽

Serum Samples ◽

Viral Haemorrhagic Fever ◽

Cchf Virus ◽

Crimean Congo Haemorrhagic Fever

SUMMARYIn the course of investigating suspected cases of viral haemorrhagic fever in South Africa patients were encountered who had been bitten by ticks, but who lacked evidence of infection with Crimean–Congo haemorrhagic fever (CCHF) virus or non-viral tick-borne agents. Cattle sera were tested by enzyme-linked immunoassay to determine whether tick-borne viruses other than CCHF occur in the country. The prevalence of antibody in cattle sera was 905/2116 (42·8%) for CCHF virus, 70/1358 (5·2%) for Dugbe, 21/1358 (1·5%) for louping ill, 6/450 (1·3%) for West Nile, 7/1358 (0·5%) for Nairobi sheep disease, 3/625 (0·5%) for Kadam and 2/450 (0·4%) for Chenuda. No reactions were recorded with Hazara, Bahig, Bhanja, Thogoto and Dhori viruses. The CCHF findings confirmed previous observations that the virus is widely prevalent within the distribution range of ticks of the genusHyalomma, while antibody activity to Dugbe antigen was detected only within the distribution range of the tickAmblyomma hebraeum. Cross-reactivity for the nairoviruses, Hazara, Nairobi sheep disease and Dugbe, was detected in serum samples from 3/72 human patients with confirmed CCHF infection, and serum from 1/162 other patients reacted monospecifically with Dugbe antigen. The latter patient suffered from febrile illness with prolonged thrombocytopenia.

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Molecular epidemiology of Crimean-Congo haemorrhagic fever virus in India

Epidemiology and Infection ◽

10.1017/s0950268816001886 ◽

2016 ◽

Vol 144 (16) ◽

pp. 3422-3425 ◽

Cited By ~ 1

Author(s):

P. SINGH ◽

M. CHHABRA ◽

P. SHARMA ◽

R. JAISWAL ◽

G. SINGH ◽

...

Keyword(s):

Eastern Europe ◽

N Gene ◽

Western India ◽

Haemorrhagic Fever ◽

Rt Pcr ◽

Study Region ◽

Phylogenetic Relatedness ◽

Cchf Virus ◽

Crimean Congo Haemorrhagic Fever ◽

First Time

SUMMARYCrimean-Congo haemorrhagic fever (CCHF) is an emerging zoonotic disease in India which is prevalent in neighbouring countries. CCHF virus (CCHFV) is a widespread tick-borne virus which is endemic in Africa, Asia, Eastern Europe and the Middle East. In the present study, samples of clinically suspected human cases from different areas of northern-western India were tested for the presence of CCHFV by RT–PCR through amplification of nucleocapsid (N) gene of CCHFV. Positive samples were sequenced to reveal the prevailing CCHFV genotype(s) and phylogenetic relatedness. A phylogenetic tree revealed the emergence of diverse strains in the study region showing maximum identity with the Pakistan, Afghanistan and Iran strains, which was different from earlier reported Indian strains. Our findings reveal for the first time the emergence of the Asia 1 group in India; while earlier reported CCHFV strains belong to the Asia 2 group.

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Viraemic transmission of Crimean-Congo haemorrhagic fever virus to ticks

Epidemiology and Infection ◽

10.1017/s0950268800048524 ◽

1991 ◽

Vol 106 (2) ◽

pp. 373-382 ◽

Cited By ~ 33

Author(s):

A. J. Shepherd ◽

R. Swanepoel ◽

S. P. Shepherd ◽

P. A. Leman ◽

O. Mathee

Keyword(s):

Ixodid Tick ◽

Transovarial Transmission ◽

Haemorrhagic Fever ◽

Transmitted Infection ◽

Hyalomma Truncatum ◽

Virus Content ◽

Cchf Virus ◽

Rhipicephalus Evertsi Evertsi ◽

Crimean Congo Haemorrhagic Fever ◽

Tick Vectors

SUMMARYIn order to determine the way in which vertebrates infected with Crimean-Congo haemorrhagic fever (CCHF) virus and potential ixodid tick vectors interact in nature, immature and adult ticks of several species were fed on viraemic mammals and then assayed for virus content at varying times after feeding. CCHF virus was not isolated from ticks of six species tested after feeding as adults and immature forms on sheep with viraemia of 102·5−3·2LD 50/ml, nor from larval ticks fed on guinea-pigs and white-tailed rats with viraemia of 101·9−2·7LD 50/ml. In contrast, virus was isolated from 10 of 152 pools of engorged adult ticks of 5 species that fed on cattle with viraemia of 101·5−2·7LD 50/ml and from 3 of 137 female ticks after oviposition. Infection was transmitted to larval and nymphalHyalomma truncatumandH. marginatum rufipes, but not toRhipicephalus evertsi evertsi, from a scrub hare with viraemia of 104·250/ml but only nymphalH. truncatumandH. m. rufipesbecame infected from scrub hares with viraemia of 102·6−2·7LD 50/ml. Infection was transmitted trans-stadially inH. m. rufipesandH. truncatuminfected as nymphae, and adultH. m. rufipestransmitted infection to a sheep. No evidence of transovarial transmission was found in larval progeny of ticks exposed to CCHF virus as adults on sheep and cattle or as immatures on scrub hares.

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Environmental and demographic risk factors associated with the prevalence of Cryptosporidium infection in the Alice rural settlements of the Eastern Cape Province of South Africa: a pilot study

Reviews on Environmental Health ◽

10.1515/reveh.2011.017 ◽

2011 ◽

Vol 26 (2) ◽

Cited By ~ 5

Author(s):

Beauty Omoruyi ◽

Fredrick Matongo ◽

Noxolo T. Nkwetshana ◽

Ezekiel Green ◽

Anna M. Clarke ◽

...

Keyword(s):

Risk Factors ◽

South Africa ◽

Pilot Study ◽

Eastern Cape Province ◽

Cryptosporidium Infection ◽

Eastern Cape ◽

Rural Settlements ◽

Factors Associated ◽

Demographic Risk ◽

Demographic Risk Factors

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Risk Factors Associated With Dengue Fever Outbreak in Taiz Governorate, Yemen, 2018: Case-control Study

10.21203/rs.3.rs-624873/v1 ◽

2021 ◽

Author(s):

Abdulkareem Ali Hussein Nassar ◽

Amr Abdulaziz Torbosh ◽

Yassin Abdulmalik Mahyoub ◽

Mohammed Abdullah Al Amad

Keyword(s):

Risk Factors ◽

Dengue Fever ◽

Case Control Study ◽

Significant Risk ◽

Case Fatality ◽

Case Control ◽

Case Definition ◽

P Value ◽

Factors Associated ◽

Control Study

Abstract Background: Dengue Fever (DF) is a significant health problem in Yemen especially in the coastal areas. On November 6, 2018, Taiz governorates surveillance officer notified the Ministry of Public Health and Population on an increase in the number of suspected DF in Al Qahirah and Al Mudhaffar districts, Taiz governorate. On November 7, 2018, Field Epidemiology Training Program sent a team to perform an investigation. The aims were to confirm and describe the outbreak by person, place and time in Taiz governorate, and identify its risk factors.Methodology: Descriptive and case-control study (1:2 ratio) were conducted. WHO case definition was used to identify cases in Al Qahirah or Al Mudhaffar districts during August-November 2018. Control was selected from the same districts who did not suffer from DF. Predesigned questionnaire was used to collect data related to sociodemographic, behavioral and environmental characteristics. Bivariate and multivariate backward stepwise analyses were used. The adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) were calculated. A P value < 0.05 was considered as the cut point for statistically significant. Epi info version 7.2 was used.Results: A total of 50 DF cases were found. Almost 52% were males and 76% were <30 years of age. The overall attack rate was 1/10,000 of the population. Case fatality rate was 4%. In multivariate analysis, not working (aOR = 26.6, 95% CI: 6.8–104.7), not using mosquito repellent (aOR = 13.9, 95% CI:1.4–136.8), wearing short sleeves/pants (aOR = 27.3, 95% CI: 4.8–156.8), poor sanitation (aOR = 5.4, 95% CI: 1.4–20.3), presence of outdoor trees (aOR = 13.2, 95% CI: 2.8–63.0) and houses without window nets (aOR = 15.7, 95% CI: 3.9–63.4) were statistically significant risk factors associated with DF outbreak. Eleven 11 (58%) of blood samples were positive for DF IgM.Conclusions: DF outbreak in Al Qahirah and Al Mudhaffar districts, Taiz governorate was confirmed. This study provides evidence-based information regarding the identified risk factors that contributed to the occurrence of this outbreak. Raising community awareness on the importance of personal protection measures and improving the sanitation services are strongly recommended.

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