Swine Is a Possible Source of Hepatitis E Virus Infection by Comparative Study of Hepatitis A and E Seroprevalence in Thailand

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in developing countries are associated with contaminated food or water. Although Thailand is non-endemic for HEV, sporadic infections may occur from zoonotic transmission. Individuals between 7 months to 69 years (mean age = 32.8) from predominantly Islamic Narathiwat (n = 305) and swine farm-dense Lop Buri (n = 416) provinces were screened for anti-HEV and anti-HAV antibodies by commercial enzyme-linked immunosorbent assay and automated chemiluminescent microparticle immunoassay, respectively. Seroprevalence and relative antibody titers were analyzed according to age groups. HAV IgG antibody positive rates in Lop Buri and Narathiwat residents were 39.9% and 58%, respectively (p < 0.001). Greater than 90% of individuals >50 years old in both provinces possessed anti-HAV IgG. In contrast, seroprevalence for anti-HEV IgG was much higher in Lop Buri (37.3%) than in Narathiwat (8.9%) (p < 0.001). Highest anti-HEV IgG prevalence was found among 21-30 year-olds (50%) in Lop Buri and 41-50 year-olds (14.1%) in Narathiwat. In summary, fewer individuals possessed anti-HEV IgG in Narathiwat where most residents abstained from pork and fewer swine farms are present. Therefore, an increased anti-HEV IgG seroprevalence was associated with the density of swine farm and possibly pork consumption. Adults were more likely than children to have antibodies to both HEV and HAV.     

Seroprevalence of antibodies to hepatitis A and E viruses in pediatric age groups in Turkey

Hepatitis A and hepatitis E are enteric transmitted viral diseases occurring in epidemic and sporadic forms especially in developing countries. Previous studies in Turkey showed that most residents are infected with HAV by the second decade of life. Since HEV is generally transmitted by the same route as HAV we conducted a community-based seroprevalence study for HAV and HEV infection in Ahatli area in Antalya, Turkey where socioeconomic conditions are low. Anti-HAV total immunoglobulin was tested by using a microparticle EIA (Axsym-Abbott Lab). Anti-HEV IgG was assayed by a micro ELISA method (Genelabs-Singapore). Of the 338 sera tested, 112 (33.1%) were positive for anti-HAV total antibody. Anti-HEV IgG was detected in three (0.89%) of the serum samples. Seropositivity rates of HAV in preschool and school children were 19.9% and 43.9% respectively (p < 0.001). No antibody to HEV was detected in preschool children, while the prevalence of anti-HEV IgG was 1.6% in children attending school. Our data showed that seroprevalence of anti-HAV is high among children samples but HEV infection appears to be relatively rare in pediatric age groups.     

Shifting seroepidemiology of hepatitis A in Japan, 1973-2003

BACKGROUND: Hepatitis A infection is caused by hepatitis A virus (HAV) contracted through fecal-oral transmission. Life-long immunity is conferred after infection. Improved sanitary conditions have generally resulted in a significant decline in the incidence of hepatitis A. However, a low incidence of infection results in increased HAV susceptibility. The present study investigates the prevalence of anti-HAV antibody and clarifies the current HAV status and HAV susceptibility in Japan at 2003. METHODS: A total of 2,430 serum specimens collected during 2003 from Japanese individuals ranging in age from 0-92 years, were tested for anti-HAV antibody using an inhibition enzyme linked immunosorbent assay. All specimens were obtained from the WHO and the National Serum Reference Bank/National Institute of Infectious Diseases, Tokyo, Japan. RESULTS: The overall seroprevalence was 12.2%. Anti-HAV antibodies were rarely detected in individuals between 0-44 years of age. Starting from the age of 45-49 years, seropositivity gradually increased through age 65 years and above. Seroprevalence was not affected by gender, and geographic distribution did not affect age-specific seroprevalence until the age of 60 years. CONCLUSIONS: HAV susceptibility in Japan is increasing annually. Particularly, the prevalence of anti-HAV antibody in individuals older than 50 years in 2003 was 50.3%, which is significantly lower than that of corresponding studies in 1994 (74.3%), 1984 (96.9%) and 1973 (96.9%). The growing susceptible population of advanced age results in more frequent HAV infection among them. The surveillance of anti-HAV antibody prevalence is useful for implementing preventive measures and for controlling the spread of HAV.     

Seroepidemiology of hepatitis A virus in Japan

A seroepidemiologic study to detect class-specific antibody against hepatitis A virus (HAV) was made with 831 randomly collected sera (415 in 1973 and 416 in 1984) from healthy Japanese. Competitive-inhibition, IgG, IgA, and IgM anti-HAV enzyme-linked immunosorbent assays (ELISA) were used. Both collections showed a low prevalence of IgG anti-HAV in young age groups and it increased rapidly at middle age and plateued at greater than or equal to 94% prevalence in the older age groups. However, two age groups spanning ages 25-34 demonstrated statistically lower IgG anti-HAV age prevalences in 1984 vs 1973 (P less than 0.001), with an average 10-year prevalence shift. These data suggest that there has been no significant level of HAV infection to alter antibody prevalences in Japan from 1973 to 1984. The markedly decreased incidence of HAV infection in Japan has created a presently large and growing population of HAV susceptibles.     

High prevalence of antibodies against hepatitis A virus among captive nonhuman primates

Hepatitis A virus (HAV) can infect not only humans but also several other nonhuman primates. This study has been conducted to evaluate the comprehensive anti-HAV seroprevalence in captive nonhuman primate populations in Thailand. The prevalence of antibodies against HAV in 96 captive nonhuman primates of 11 species was evaluated by competitive enzyme immunoassay (EIA). HAV antibodies were found in 64.7% (11/17) of macaques, 85.7% (6/7) of langurs, 28.4% (10/35) of gibbons, and 94.6% (35/37) of orangutans. However, anti-HAV IgM was not found in any sera. These results indicate that the majority of captive nonhuman primates in Thailand were exposed to HAV. It is possible that some of the animals were infected prior to capture.     

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.     

Seroepidemiological markers of enterically transmitted viral hepatitis A and E in individuals living in a community located in the North Area of Rio de Janeiro,RJ, Brazil

We investigated the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in subjects living in the community of Manguinhos, Rio de Janeiro, Brazil, and assisted at the Health Unit of Escola Nacional de Saúde Pública, Funda??o Oswaldo Cruz. After formal consent, individuals were submitted to an interview using a standardized questionnaire. Anti-HAV and anti-HEV antibodies were detected by ELISA. Statistical analysis was carried out using the Epi-Info 6.04b software, to investigate possible associations between serological markers and risk factors. Results were regarded as significant when p value < 0.05. Although a high prevalence of anti-HAV was observed (87%), almost 50% of subjects under the age of 10 were susceptible to HAV infection, an unexpected rate in endemic areas. This fact could be attributed to improvements in environmental sanitation, occurring in this area in the last years. The increasing proportion of susceptible people may result in outbreaks of HAV infection, since the virus still circulates in this area, as verified by the detection of anti-HAV IgM in some individuals. No statistical association was met between HAV infection and the risk factors here assessed. The anti-HEV IgG prevalence found in this population was 2.4%, consistent with the one found in non-endemic areas.     

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.     

Seroprevalence of Fecal-Oral Transmitted Hepatitis A and E Virus Antibodies in Burkina Faso

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections occur chiefly as a result of unhygienic conditions. The purpose of this study was to assess the seroprevalence of antibodies to both viruses in central Burkina Faso in the absence of a recorded hepatitis epidemic. Serum samples from 178 blood donors (131 males and 47 females) and from 189 pregnant women were collected from November 2010 to March 2012, at blood banks and medical centers in Burkina Faso. An immunochromatography test was used to screen for Anti-HAV IgM and IgG in a subgroup of 91 blood donors and 100 pregnant women. The seroprevalence of anti-HAV IgG was 14.3% [CI95, 7.1–21.4%] for all blood donors and 23% [CI95, 14.8–31.2%] for pregnant women. Anti-HEV IgG were detected using the ELISA kits Dia.pro and Wantai and were found in 19.1% [CI95, 13.3–24.9%] of the blood donors and 11.6% [CI95, 7.1–16.2%] of the pregnant women. The seroprevalences of anti-HAV and anti-HEV IgGs did not differ significantly between men and women blood donors. Anti-HAV IgM was detected in 3.3% of the blood donors and in 2% of the pregnant women. These findings for asymptomatic individuals indicate that the HAV and HEV circulate at low but significant levels. This is the first evaluation of the acute hepatitis virus burden in Burkina Faso and the underlying epidemiologic status of the population.     

Prevalence of Helicobacter in Laboratory Micein Thailand

Prevalence of Helicobacter is mostly unknown in laboratory animals in Thailand. The 221 mice feces/cecum from 8 universities, 2 pharmaceutical companies and 3 research institutions in Thailand were surveyed for the prevalence and distribution of Helicobacter species by using the Electrochemical DNA chip. Helicobacter were detected 23/46 samples in Specific Pathogen Free (SPF) and 168/175 in conventional condition. Prevalence of Helicobacter were 98%, 96%, 92% and 78% in South (n=40), Northeast (n=40), North (n=25) and Central area (n=116), respectively. Only Central area holds SPF facility resulting in Helicobacter prevalence that seems to be lower than other areas. Three species of Helicobacter were detected in feces/cecum samples by sequence analysis: H. rodentium (67.0%, 148 samples), Helicobacter sp. MIT 01-6451 (15.4%, 34 samples), and unidentified Helicobacter species (14.1%, 9 samples). The results suggested that H. rodentium is the most common species of Helicobacter in laboratory mice in Thailand.     

The association between temperature and mortality in tropical middle income Thailand from 1999 to 2008

We have investigated the association between tropical weather condition and age-sex adjusted death rates (ADR) in Thailand over a 10-year period from 1999 to 2008. Population, mortality, weather and air pollution data were obtained from four national databases. Alternating multivariable fractional polynomial (MFP) regression and stepwise multivariable linear regression analysis were used to sequentially build models of the associations between temperature variable and deaths, adjusted for the effects and interactions of age, sex, weather (6 variables), and air pollution (10 variables). The associations are explored and compared among three seasons (cold, hot and wet months) and four weather zones of Thailand (the North, Northeast, Central, and South regions). We found statistically significant associations between temperature and mortality in Thailand. The maximum temperature is the most important variable in predicting mortality. Overall, the association is nonlinear U-shape and 31 °C is the minimum-mortality temperature in Thailand. The death rates increase when maximum temperature increase with the highest rates in the North and Central during hot months. The final equation used in this study allowed estimation of the impact of a 4 °C increase in temperature as projected for Thailand by 2100; this analysis revealed that the heat-related deaths will increase more than the cold-related deaths avoided in the hot and wet months, and overall the net increase in expected mortality by region ranges from 5 to 13 % unless preventive measures were adopted. Overall, these results are useful for health impact assessment for the present situation and future public health implication of global climate change for tropical Thailand.     

Seroprevalence Rates of Helicobacter pylori and Viral Hepatitis A among Adolescents in Three Regions of the Kingdom of Saudi Arabia: Is There Any Correlation?

Background: The seroprevalence rate of Helicobacter pylori in the Kingdom of Saudi Arabia (KSA) was reported to be in the range of 50–80% among mostly symptomatic patients in non‐community‐based studies. However, the seroprevalence of viral hepatitis A (HAV) underwent a marked decline in the last two decades from over 50% in 1989 to 25% in 1997 among Saudi children under the age of 12 years. The aim of this paper was to study seroprevalence rates of H. pylori and HAV among the adolescent population in three regions of KSA and to determine whether there was any correlation between them. Materials and methods: We randomly selected 1200 16–18‐year‐old students from three regions around KSA. Demographic data, including socioeconomic status (SES), were recorded, and each student was tested for the presence of H. pylori‐IgG antibodies and anti‐HAV‐IgG. Results: The results indicate a high H. pylori infection rate (47%) among this age group. Boys had a higher prevalence than girls (p = .03), and the Al‐Qaseem region had the highest prevalence (51%, p = .002). SES did not contribute to the high prevalence rates (p = .83). A cross‐tabulation of data showed that 88 (8%) of the teenagers were seropositive and that 512 (44%) were negative for both H. pylori and HAV antibodies (χ² = 0.03, OR = 0.97, CI = 0.70–1.34). The agreement between H. pylori and HAV seropositivity was lower than would be predicted by chance (κ = ?0.03). The variables that were independently associated with seropositivity to H. pylori were being female (OR = 0.75, 95% CI = 0.60–0.95) and living in the Madinah region (OR = 0.72, 95% CI = 0.55–0.94). Conclusion: The prevalence of H. pylori in this group of adolescents was high. However, there was no correlation between H. pylori and HAV infection rates. Hence, factors contributing to the transmission source and route seem to be different.     

Modelling the Force of Infection for Hepatitis A in an Urban Population-Based Survey: A Comparison of Transmission Patterns in Brazilian Macro-Regions

Background

This study aimed to identify the transmission pattern of hepatitis A (HA) infection based on a primary dataset from the Brazilian National Hepatitis Survey in a pre-vaccination context. The national survey conducted in urban areas disclosed two epidemiological scenarios with low and intermediate HA endemicity.

Methods

A catalytic model of HA transmission was built based on a national seroprevalence survey (2005 to 2009). The seroprevalence data from 7,062 individuals aged 5–69 years from all the Brazilian macro-regions were included. We built up three models: fully homogeneous mixing model, with constant contact pattern; the highly assortative model and the highly assortative model with the additional component accounting for contacts with infected food/water. Curves of prevalence, force of infection (FOI) and the number of new infections with 99% confidence intervals (CIs) were compared between the intermediate (North, Northeast, Midwest and Federal District) and low (South and Southeast) endemicity areas. A contour plot was also constructed.

Results

The anti- HAV IgG seroprevalence was 68.8% (95% CI, 64.8%–72.5%) and 33.7% (95% CI, 32.4%–35.1%) for the intermediate and low endemicity areas, respectively, according to the field data analysis. The models showed that a higher force of infection was identified in the 10- to 19-year-old age cohort (∼9,000 infected individuals per year per 100,000 susceptible persons) in the intermediate endemicity area, whereas a higher force of infection occurred in the 15- to 29-year-old age cohort (∼6,000 infected individuals per year per 100,000 susceptible persons) for the other macro-regions.

Conclusion

Our findings support the shift of Brazil toward intermediate and low endemicity levels with the shift of the risk of infection to older age groups. These estimates of HA force of infection stratified by age and endemicity levels are useful information to characterize the pre-vaccination scenario in Brazil.     

Ebola and Marburg virus antibody prevalence in selected populations of the Central African Republic

With the natural history of the filovirus family seemingly unknown, filovirus ecology in its natural environment remains a rudimentary field of research. In order to investigate the maintenance cycle of filovirus in Central Africa, a study was conducted within the rain forest of the Central African Republic. The epidemiological study determines the frequency and distribution of filovirus seroprevalence in a selected human population. Using an ELISA, serum samples from Pygmy and non-Pygmy populations were tested for Ebola-Zaire virus and Marburg (MBG) virus antibody. Filovirus antibody reacting sera were found in all zones investigated, and in all populations studied (Ebola virus IgG 5.3%; Marburg virus IgG 2.4%). Pygmies appeared to have a significantly higher seroprevalence (P < 0.03) against Ebola-Zaire virus (7.02%) than non-Pygmies (4.2%). MBG virus or related unknown filovirus strains also seem to be present in the western part of Central Africa. MBG virus antibodies were present in different Pygmy groups (ranging from 0.7 to 5.6%, mean 2.05%) and in several non-Pygmy populations (ranging from 0.0 to 3.9%, mean 3.4%) without an overall significant difference between the two groups (P = 0.14). The potentialities of nonpathogenic filovirus strains circulating in the Central African Republic are discussed.     

Enzootic hepatitis A infection in cynomolgus monkeys (Macaca fascicularis)

During a toxicology study in cynomolgus (long-tailed or crab-eating) monkeys (Macaca fascicularis), a randomly distributed incidence of significantly increased hepatic enzyme activity was observed. Premedication hepatic enzyme activity in all monkeys of this study was normal, but increased alanine aminotransferase (ALT) activity was found in 4 of the 24 animals 2 weeks after initiation of the study and in 10 of 24 at 4 weeks. A drug-related effect was considered unlikely initially because the increases were not doserelated, and a 3-year review of 655 cynomolgus monkeys revealed a 15–20% incidence of increased hepatic enzyme activity. Good correlation was subsequently established between increased hepatic enzyme activity, active hepatitis A virus (HAV) infection, and histomorphologic confirmation of hepatitis (chronic periportal inflammation). Follow-up viral serodiagnostic screening of resident macaques revealed an overall incidence of anti-HAV IgG in 80% (155/193) of cynomolgus and in 70% (14/20) of rhesus monkeys. Serial screening demonstrated that several initially negative monkeys became seropositive for anti-HAV IgG, and a few acquired active infection (anti-HAV IgM). Among newly acquired cynomolgus monkeys, 2.5% (2/80) had an acute HAV infection, and 35% (28/80) eventually tested positive for anti-HAV IgG while quarantined in the primate facility. The characterization of an enzootic HAV infection in incoming monkeys posed a significant risk for the primate colony and handlers. Rigorous sanitation, isolation, and quarantine procedures, including personnel training and additional protective clothing for personnel working in the primate colony, reduced tho potential for transmission and arrested the outbreak. Experimenters should be cautious in ascribing toxicity to a test article based solely on increased hepatic enzyme activity associated with chronic periportal inflammation.     

Pichia pastoris酵母中表达人源中和性抗甲型肝炎病毒scFv-Fc融合抗体的研究

为了探讨人源抗甲型肝炎（甲肝）病毒scFv—Fc融合抗体在酵母中的表达特性,将获得的人源抗甲肝病毒中和性单链可变区抗体（scFv抗体）基因克隆入含信号肽及人IgG1Fc抗体基因的酵母细胞表达载体中,获得了一株中和性人源抗甲肝病毒pPiscFv—FcHA16融合抗体的分泌表达,并对表达产物进行了纯化。同时对表达产物的生物学特性进行了一系列鉴定。表达的pPiscFv—FcHA16融合抗体为具有不同糖基化形式的同源二聚体,与相应的CHO细胞表达的IgG抗体相比,pPiscFv—FcHA16融合抗体仍保持很好的抗原结合活性,以及与中和性鼠抗甲肝病毒单克隆抗体的竞争抑制能力。同时也保持了对甲肝病毒的体外中和活性。这些结果表明,在酵母中表达的单链可变区（scFv）与IgG1Fc区的融合抗体具有很好的生物学活性,有希望用做体外诊断,用纯化相应的抗原,或者可能用于体内预防与治疗。     

Cytomegalovirus IgM Seroprevalence among Women of Reproductive Age in the United States

Cytomegalovirus (CMV) IgM indicates recent active CMV infection. CMV IgM seroprevalence is a useful marker for prevalence of transmission. Using data from the National Health and Nutrition Examination Survey (NHANES) III 1988–1994, we present estimates of CMV IgM prevalence by race/ethnicity, provide a comparison of IgM seroprevalence among all women and among CMV IgG positive women, and explore factors possibly associated with IgM seroprevalence, including socioeconomic status and exposure to young children. There was no difference in IgM seroprevalence by race/ethnicity among all women (3.1%, 2.2%, and 1.6% for non-Hispanic white, non-Hispanic black and Mexican American, respectively; P = 0.11). CMV IgM seroprevalence decreased significantly with increasing age in non-Hispanic black women (P<0.001 for trend) and marginally among Mexican American women (P = 0.07), while no apparent trend with age was seen in non-Hispanic white women (P = 0.99). Among 4001 IgG+ women, 118 were IgM+, resulting in 4.9% IgM seroprevalence. In IgG+ women, IgM seroprevalence varied significantly by age (5.3%, 7.3%, and 3.7% for women of 12–19, 20–29, and 30–49 years; P = 0.04) and race/ethnicity (6.1%, 2.7%, and 2.0% for non-Hispanic white, non-Hispanic black, and Mexican American; P<0.001). The factors reported associated with IgG seroprevalence were not associated with IgM seroprevalence. The patterns of CMV IgM seroprevalence by age, race/ethnicity, and IgG serostatus may help understanding the epidemiology of congenital CMV infection as a consequence of vertical transmission and are useful for identifying target populations for intervention to reduce CMV transmission.     

Helicobacter pylori and hepatitis A virus infection in school-aged children on two isolated neighborhood islands in Taiwan

Background. The transmission routes of Helicobacter pylori and hepatitis A virus (HAV) infections have been extensively discussed in previous literature. However, whether H. pylori and HAV shared the same transmission pattern or not remains unclear. Lower socioeconomic status was recognized as a consistent risk factor to both infections. However, whether fecal‐oral transmission was a risk factor to both infections is still under debate. Materials and Methods. In 1996, we conducted a cross‐sectional study to evaluate the seroprevalence of antibody to H. pylori and HAV among the randomly selected school‐aged children (age between 13 and 15) on Green Island (n = 91) and Lanyu Island (n = 138) (two isolated neighborhood islands near Taiwan Main Island). Results. The seroprevalence of H. pylori and HAV on the Green Island were 82.4% and 5.5%, respectively. The seroprevalence of H. pylori and HAV on Lanyu Island were 71.0% and 90.6%, respectively. H. pylori seroprevalence of all children and the subgroup of 13‐year‐olds was significantly lower on Lanyu Island than Green Island. However, it was not significantly different in subgroups of 14‐ and 15‐year‐olds. HAV seroprevalence was significantly higher on Lanyu Island than Green Island among all children and in each age subgroup. The correlation of H. pylori infection and HAV infection did not demonstrate significant linear correlation on both islands. Conclusions. In conclusion, H. pylori and HAV infections in school‐aged children of 13–15 years of age on Green Island and Lanyu Island did not demonstrate significant correlation. The results of this study imply that H. pylori and HAV may share different transmission routes of infection.     

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.