Seropositive Cattle Research Articles

Cattle, sheep, and goat humoral immune responses against SARS-CoV-2

Following the emergence of SARS-CoV-2 in late 2019, several species of domestic and wild animals have been found to be susceptible to SARS-CoV-2 infection through experimental inoculation and animal surveillance activities. Detection of SARS-CoV-2 specific antibodies in animals is an important surveillance tool since viral shedding in animals can only be detected for a short period of time. In this study, convenience serum samples were collected from 691 cattle, 698 sheep, and 707 goats from several regions in the United States, between 2019 to 2022. The samples were evaluated for the presence of SARS-CoV-2 specific antibodies using two commercial enzyme-linked immunosorbent assays (ELISA); one based on the inhibition of the SARS-CoV-2 receptor-binding domain (sVNT) and the other based on the nucleocapsid protein (N-ELISA) of SARS-CoV-2. Positive samples from the sVNT were additionally evaluated using a conventional virus neutralization test (VNT) employing the Wuhan-like SARS-CoV-2 USA/WA1/2020 isolate. Our results indicate that ∼1% (6/691) of cattle, ∼2% (13/698) of sheep, and ∼2.5% (18/707) of goat serum samples were positive when using the sVNT, whereas ∼4% of cattle (25/691) and sheep (27/698), and 2.5% (18/707) of goat serum samples tested positive with the N-ELISA. None of the sVNT positive cattle, sheep, or goat serum samples had detectable neutralizing antibody activity (<1:8) against the SARS-CoV-2 USA/WA1/2020 isolate by the VNT. Our results indicate low seropositivity in cattle, sheep, and goats in the U.S., indicating the importance to continue monitoring for SARS-CoV-2 prevalence in animal species that are in close contact with humans.

An estimation of vertical transmission of Neospora caninum in dairy cattle, in Khorasan Razavi Province, Iran

Neospora caninum is an important agent of abortion and reproductive loss in dairy cattle. The objective of this study was to determine the rate of vertical transmission of N.caninum in dairy cattle, KorasanRazavi province, Iran. Two dairy farms with history of Neospora abortion were selected and two hundred -eighty blood samples of dairy cattle in the third trimester of gestation were collected from January 2018 to April 2019. The serum samples of each dairy cattle were examined by an indirect ELISA. At the calving, the colostrum samples of seropositive dams with blood samples of their precolostral calves were collected and again examined by the ELISA method. The seroprevalence of Neospora infection was determined by 16.59% (41/247) in dairy farm 1 and 12.12% (4/33) in dairy farm 2 (P&gt;0.05). In the present study, 100% of precolostral calves born of seropositive dairy cattle had antibodies against Neospora caninum before colostrum ingestion. Based on the seroprevalence of dam and daughter, the vertical transmission was estimated at the highest rate (100%). In conclusion, the results are shown the importance of vertical transmission to remain and contribute to N.caninum infection in two dairy farms.

Seroprevalence and risk factors for brucellosis in cattle and rodents in Kilosa district, Morogoro, Tanzania

Background: Brucellosis is a global zoonosis caused by gram-negative bacteria that affects a diverse array of hosts including humans, domestic animals as well as wild animals such as cattle (B. abortus), goats, and sheep (B. melitensis), pigs (B. suis), and rodents (B. neotomae), and results in financial setbacks in the livestock industry. This study aimed to identify risk factors and estimate the seroprevalence of brucellosis in cattle and rodents in Kilosa district, Tanzania. Methods: A cross-sectional study was conducted from January 2023 to March 2023, cattle were randomly selected and rodents were trapped using Sherman, wire cages, and havahart traps. Blood samples were collected from the jugular vein and heart of the cattle and rodents, respectively. Sera were harvested from the collected blood and stored at – 20 ºC. All the sera were screened for brucella antibodies using the Rose Bengal Plate Test (RBPT) and confirmed by competitive Enzyme Linked Immuno Sorbent Assay (c-ELISA). The risk factors were captured using a structured questionnaire and analyzed by computing the Chi-square test and generalized linear model. Results: The seroprevalence of brucellosis was found to be 5.31% in cattle (95% CI: 0.0286-0.089) and 0.72% in rodents (95% CI: 0.0002-0.0397). A significant association was observed between grazing style and brucellosis seropositivity in cattle, with cattle that grazed together with sheep and goats having significantly higher odds of seropositivity (OR=6.5; 95% CI: 1.74-42.17, **p &lt; 0.01). Conclusion: The detection of Brucella antibodies in both species indicates ongoing transmission and potential risk to public health. Our findings suggest that rodents may serve as reservoirs of brucellosis, contributing to its persistence and spread. Further research is essential to characterize the specific brucella species circulating among cattle and rodents and to understand the dynamics of interspecies transmission.

Detection and characterization of Brucella species in rodents: A threat for the persistence of brucellosis in livestock farms

Brucellosis, caused by various Brucella species, poses a significant threat to global public health and livestock industries. This study aims to fill the knowledge gap concerning the presence of Brucella spp. in rodents on livestock farms in Iran. Both bacteriological and molecular surveys were conducted to assess the prevalence of Brucella spp. in these rodent populations. A total of 16 rodents were captured in four seropositive dairy cattle farms (n = 7) and two seropositive sheep farms (n = 9) and were then examined for the presence of the Brucella-infection. Five cow milk samples and 53 bovine lymph node samples from these farms were also tested for Brucella spp. Lymph node samples from dairy cattle farms contained 32 B. abortus biovar 3 isolates and one B. melitensis Rev1 vaccine isolate. The bacterial culture of rodents identified 12.5% of them (Mus musculus and Rattus norvegicus) harboring Brucella strains in dairy cattle farms. The rodents had B. abortus biovar 3 and B. melitensis biovar 1, suggesting a reservoir for these bacteria. A two-step molecular assay, utilizing the Omp28 sequences in tissue samples of rodents, demonstrated that 68.75% (n = 11) of the tested rodents yielded positive results. Bruce-ladder PCR and wboA typing on isolated bacteria revealed a close relationship to field strain of Brucella species. The study reveals that rodents on seropositive livestock farms in Iran harbor Brucella spp., indicating a potential reservoir for these bacteria. This highlights the importance of monitoring rodent populations through the molecular and bacterial methods to manage and control brucellosis in livestock.

Prevalence and risk factors for Anaplasma marginale seropositivity in cattle in California

Bovine anaplasmosis, a tick-borne disease caused by Anaplasma marginale, imposes considerable economic bur­den on cattle industries throughout the world. Clinical signs of bovine anaplasmosis include fever, weight loss, lethargy, jaundice, abortion and death. The severity of the disease in­creases with age, and calves under 1 year of age generally do not progress to clinical disease or develop mild disease. Once infected, cattle remain persistently infected carriers for life. Climate change and drought conditions may affect the distri­bution and prevalence of tick populations and tick-borne dis­eases and re-evaluating the seroprevalence of Anaplasma would provide a better understanding of the disease dynamics in California. To our knowledge, there has been no updated study regarding the distribution of Anaplasma infection status in California since 2008, and the information on weather factors related to the disease is also limited. There is an urgent need to evaluate the prevalence of Anaplasma infection in different regions of California. The goal of this study is to estimate the seroprevalence of Anaplasma infection in California cattle over time, and the specific goal is to identify potential risk factors for infection including animal demographics, region, Anaplasma seroprevalence of wild ruminants, Dermacentor tick species presence, and weather effects.

Impact of herd mobility on brucellosis seroprevalence and spread risk resulting from cross-border transhumance.

Cross-border livestock mobility through transhumance is mainly practiced in West African countries for seasonal access to resources and market. Cross-border herds are involved in the dynamic of transboundary animal diseases among them brucellosis taken as model. Brucellosis is a zoonotic disease causing abortion. This study explores the seroprevalence of brucellosis according to mobility and infection spread between Mali and Côte d'Ivoire in the context of seasonal cross-border transhumance. From February to April 2021, a transversal serological survey of brucellosis was conducted on 521 cattle from 111 transhumant herds and 283 cattle from 59 sedentary herds, all from Mali. The global individual seroprevalence for Brucella spp. in transhumant and sedentary cattle from Mali was 8.2% (95% CI=6.0-10.5). At herd level, seroprevalence was 21.2% with a significant variation between transhumant (11.7%) and sedentary (39.0%) herds. For herds in transhumance, cattle seropositivity was associated with a previous infection suspected by herdsmen odds ratio (OR=4.4; 95% CI=1.1-18.1) and unknown abortion aetiology (OR=4.3; 95% CI=1.0-17.3). The departure region (coming from Sikasso) and previous brucellosis infection or unexplained abortion could be used to predict Brucella infection in transhumant herds with a probability of around 60%. The risk of brucellosis introduction in host regions was high despite the individual animal seroprevalence of 3.6% and a low sale rate in transhumant cattle. The findings suggest that testing transhumant during border control and survey of cattle markets and sales could improve risk control of the spread of disease at regional scale.

Parasitological and serological detection of Trypanosoma evansi on Bali cattle at the Pesanggaran slaughterhouse, Denpasar, Indonesia using hematological profile

Abstract. Apsari IAP, Suratma NA, Swacita IBN, Soma IG, Sari TK, Putra IPC, Sudipa PH. 2024. Parasitological and serological detection of Trypanosoma evansi on Bali cattle at the Pesanggaran slaughterhouse, Denpasar, Indonesia using hematological profile. Biodiversitas 25: 1057-1062. Bali cattle (Bos sondaicus Blyth, 1842 syn. Bos javanicus domesticus Wilckens, 1905) are vulnerable to blood protozoan infections like Trypanosoma evansi. Indonesia's warm and moist environment provides ideal conditions for blood-sucking flies such as Stomoxys calcitrans, Haematobia irritans, and Hipobosca sp. to thrive and spread. These flies act as carriers of T. evansi, which can then infect Bali cattle. This study aims to detect the presence of T. evansi in Bali cattle. Blood samples were collected from 275 Bali cattle at the Pesanggaran slaughterhouse, Denpasar City, Bali, Indonesia. The samples were examined using the Giemsa-Staining Blood Smear (GSBS) method and hematology profile examination using Hematology Analyzer RT-7600 for Vet. Serum samples were also collected for serologic examination using the Card Agglutination Test for Trypanosomiasis (CATT) method. The hematological profile data obtained were analyzed descriptively, and the Mann-Whitney U test was used to determine the significance of hematological values between female and male cattle seropositive to T. evansi. The results showed that the T. evansi parasite was not detected in the blood smear examination. However, the serological detection with CATT revealed that 6.54% (18/275) of Bali cattle were positive for T. evansi. The hematological profiles of T. evansi seropositive cattle remained within the normal range, except for neutrophil percentage. White Blood Cell (WBC), Hemoglobin (Hb) levels, and hematocrit (PCV) values of male cattle were significantly (P?0.05) lower than those of females. Therefore, based on serological examination, it can be concluded that the protozoa T. evansi is present in 6.54% of Bali cattle at the Pesanggaran slaughterhouse.

Can herd seroprevalence be used as an indicator of enzootic stability for bovine anaplasmosis? Insights from a case-control field study in Brazil

Bovine anaplasmosis presents a significant challenge to livestock production in tropical, subtropical, and temperate regions. For many years, the concept of enzootic stability/instability (initially established for babesiosis) and herd seroprevalence as an indicator of outbreak risks have been applied to anaplasmosis. However, this model has never been definitively validated for Anaplasma marginale. The objective of this study was to examine the relationship between herd immunity (seroprevalence) and the occurrence of anaplasmosis outbreaks in Southern Brazil. A case-control study was conducted, categorizing farms into two groups: cases (farms with a history of clinical anaplasmosis) and controls (those without anaplasmosis). Thirteen farms were identified as “cases”, while 23 were identified as “controls”. A substantial difference in seroprevalence distribution between the two groups was observed. The majority of “control” farms exhibited over 75% of animals with antibodies to A. marginale in both calves and heifers, whereas the majority of “case” farms had a seropositive cattle percentage below 75%. Additionally, twelve months after cattle serology tests, we conducted a prospective follow-up survey to identify any clinical cases of anaplasmosis. Statistical associations (P < 0.05) were found between both retrospective and prospective anaplasmosis outbreaks and the hypothetical threshold of herd seroprevalence (75%). We hypothesize that herd seroprevalence may be an indicator of the risk of occurrence of clinical anaplasmosis. It appears that the epidemiology of cattle anaplasmosis, at least in our conditions, aligns with the well-known model of enzootic stability/instability originally applied to bovine babesiosis.

Development of TaqMan probe-based RT-qPCR assays for detection of BoHV-1 latency in Bovine

Bovine herpesvirus-1 is highly contagious virus of cattle and buffaloes all over the world. It establishes lifelong latency in ganglionic neurons of the peripheral nervous system. Since, trigeminal ganglia are the main sites of latency, therefore, it is challenging to detect BoHV-1 in latently infected live animals. No research work has been done to correlate the sero-prevalence and latency in peripheral blood mononuclear cells (PBMC). The present study was designed to detect BoHV-1 latency related transcript or microRNA in peripheral blood mononuclear cells of sero-positive animals. The highly sensitive RT-qPCR assays based on TaqMan chemistry have been developed for the detection of transcripts of BoHV-1 latency. The limit of detection (LOD) of the assays for ORF-1 specific RT-qPCR and miRNA specific RT-qPCR was 460 copies and 117 copies respectively. The efficiency of the developed assays was 93.5% for ORF-1 and 97.93% for miRNA transcript. None of the PBMC samples of seropositive animals found positive for ORF-1 and miRNA transcripts in developed assays.The absence of latency specific transcripts in PBMC might be due to very low expression i.e. beyond the LOD of newly developed assays or absence of latency in PBMC of seropositive animal. However, further studies are required to establish the fact. To the best of authors knowledge, this is the first report of latency-specific RT-qPCR assay development and its application in PBMC of BoHV-1 seropositive cattle.

Observational longitudinal study on Toxoplasma gondii infection in fattening beef cattle: serology and associated haematological findings

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is a globally distributed zoonotic infection with significant implications for human and animal health. This study investigated the prevalence of T. gondii infection in a population of beef cattle at three different stages of their productive lifespan and examined the impact of T. gondii serological status on blood parameters. A commercial beef fattening unit in Italy was the setting for this research, which involved a biosecurity assessment upon cattle arrival, blood sampling at three time points and Toxoplasma-specific serological testing using indirect fluorescent antibody tests (IFAT). Results revealed a dynamic pattern of T. gondii seropositivity in cattle, with an initial prevalence of 30.6% at arrival (T0) that increased to 44.6% at 14 days (T1) and then decreased slightly to 39.3% at slaughter after 5 months (T2). Interestingly, seroconversion was observed during the study, indicating ongoing infections, and antibody waning occurred in some animals. In terms of blood parameters, seropositive cattle exhibited significantly lower mean corpuscular volume (MCV) and a higher neutrophil–lymphocyte (N/L) ratio, suggesting an activation of the innate immune response. Furthermore, cattle with higher antibody titres displayed higher neutrophil counts. However, all blood parameters with a statistical significance were within the reference range. This study provides for the first time a longitudinal investigation on the serological status for T. gondii in naturally exposed beef cattle. These findings provide valuable insights into the clinico-pathological aspects of natural T. gondii exposure in cattle and underscore the importance of monitoring and managing T. gondii infection in livestock production systems.

SEROMONITORING OF CRIMEAN-CONGO HEMORRHAGIC FEVER IN FARM ANIMALS

The article presents data from serological studies of blood sera of farm animals for the presence of antibodies to the Crimean-Congo haemorrhagic fever virus (CCHF). In 2022, 590 small cattle blood sera collected in 4 regions were examined, and in 2023, 1004 small cattle sera and 1090 cattle sera from 15 regions of Kazakhstan. As a result of the studies, it was established that the seroprevalence of CCHF virus among cattle in 2023 was 5.32%. Seropositive cattle were detected in 6 (Atyrau (9.38%), Kyzylorda (57.5%), Zhambyl (40%), Turkestan (78.58%), Almaty (4.77%), West Kazakhstan (1, 93%) from 15 studied regions. Seropositive sheep were detected in 4 regions in 2022 and in 5 out of 15 studied regions in 2023. The presence of antibodies to the CCHF virus was detected in 2022 in West Kazakhstan (4.5%), Turkestan (11 .3%), Zhambyl (30.9%) and Kyzylorda (44.3%) regions, and 2023 in West Kazakhstan (6.9%), Turkestan (14.52%), Zhambyl (15%), Kyzylorda (70%) and North Kazakhstan (12.1%) regions. The results of our research show that the distribution area of CCHF has expanded significantly. Based on the data obtained, we can conclude that two endemic regions for CCHF have formed on the territory of Kazakhstan: the southern endemic region, including Kyzylorda, Turkestan, Zhambyl, and Almaty regions, as well as the western endemic region, including West Kazakhstan and Atyrau regions. Given the constant movement of wild and farm animals within the country, there is a high risk of CCHF spreading from endemic regions to free regions. To confirm these data, it is necessary to conduct constant monitoring of farm animals, ticks, and other blood-sucking carriers of this virus.

Humoral immune response profile of a cattle herd vaccinated with 5- and 10-times Bakirköy strain sheep pox vaccine under field conditions

Vaccination is the most effective control measure for Lumpy Skin Disease (LSD). The Bakırköy strain-derived sheep pox vaccine (SPPV) has been used against LSD in Türkiye since 2013. In this study, a cattle herd was vaccinated with SPPV and 35 cattle, of which 9 and 26 received 10 and 5 sheep doses, respectively, were followed for 200 days for humoral immune responses. Additionally, maternal antibodies in colostrum-fed calves were investigated. The humoral immune responses of naive and previously vaccinated cattle were compared to determine the effects of annual re-vaccination. Furthermore, the compatibility of the VNT and ELISA tests was analyzed. According to the results, on day 30 post-vaccination, 19 and 13 out of 35 cattle were positive for VNT and ELISA, respectively. The number of seropositive cattle was higher in the group that had been vaccinated in previous years than in naive cattle. No significant differences were observed in the number of positive cattle between the groups vaccinated with the 5- and 10- doses. In colostrum-fed calves grouped according to age, the seropositivity rate was 87 % (41/47) in the one-week-old group, while this rate was only 18 % (3/16) in the 3-month-old group. It was determined that vaccination at different stages in the last four months of pregnancy did not cause any difference in the number of seropositive calves in one-week-old calves fed with colostrum. The concordance between VNT and ELISA tests was lower in 5-dose vaccinated group than 10-dose vaccinated and colostrum-fed calves groups. This study provides insights into the effect of the vaccination strategy followed by Türkiye during its combat of LSD and revealed that annual repeated vaccination using heterologous vaccine has significant positive effects on humoral immun response at the herd level.

Is Brucella excreted in cattle faeces? – Evidence from Punjab, India

Brucellosis is a neglected zoonosis that affects animals and people in much of the underdeveloped world. The disease is endemic in cattle in Punjab, India and controlling it is a public health challenge. Dairy farmers and farm labour commonly handle cattle faeces with bare hands and personal protective equipments are not used. No studies have been conducted about the shedding of Brucella species in faeces of sero positive cattle in the state. This study aimed to isolate and identify the Brucella species from faeces of sero positive cattle in Punjab, India. Faecal samples were collected from 350 Brucella sero positive cattle in Ludhiana district of Punjab, India. Isolation was performed using a pre-enriched Brucella selective broth medium as well as Brucella selective medium agar plates containing horse serum and Brucella selective supplements. Isolates were identified using Gram staining technique and rapid slide agglutination test, and then confirmed by using bcsp31 and 16s rRNA genus specific PCR. Isolates were further identified up to species level by using Bruce-Ladder multiplex PCR. Fourteen Brucella species were isolated, all of which showed coccobacilli on gram staining, positive rapid slide agglutination test and amplification of bcsp31 and 16s rRNA genes. Of the 14 isolates, 11 were identified as Brucella abortus and 3 were identified as Brucella melitensis. The study demonstrates that animal faeces could pose a potential risk for animal and human health and faeces of seropositive cattle must be handled with care.

Seroepidemiological investigation of Crimean Congo hemorrhagic fever virus in livestock in Uganda, 2017.

Crimean-Congo Hemorrhagic fever (CCHF) is an important zoonotic disease transmitted to humans both by tick vectors and contact with fluids from an infected animal or human. Although animals are not symptomatic when infected, they are the main source of human infection. Uganda has reported sporadic human outbreaks of CCHF in various parts of the country since 2013. We designed a nationwide epidemiological study to investigate the burden of CCHF in livestock. A total of 3181 animals were sampled; 1732 cattle (54.4%), 1091 goats (34.3%), and 358 sheep (11.3%) resulting in overall livestock seropositivity of IgG antibodies against CCHF virus (CCHFV) of 31.4% (999/3181). Seropositivity in cattle was 16.9% and in sheep and goats was 48.8%. Adult and juvenile animals had higher seropositivity compared to recently born animals, and seropositivity was higher in female animals (33.5%) compared to male animals (24.1%). Local breeds had higher (36.8%) compared to exotic (2.8%) and cross breeds (19.3%). Animals that had a history of abortion or stillbirth had higher seropositivity compared to those without a history of abortion or stillbirth. CCHFV seropositivity appeared to be generally higher in northern districts of the country, though spatial trends among sampled districts were not examined. A multivariate regression analysis using a generalized linear mixed model showed that animal species, age, sex, region, and elevation were all significantly associated with CCHFV seropositivity after adjusting for the effects of other model predictors. This study shows that CCHFV is actively circulating in Uganda, posing a serious risk for human infection. The results from this study can be used to help target surveillance efforts for early case detection in animals and limit subsequent spillover into humans.

Q fever and toxoplasmosis in South African livestock and wildlife: a retrospective study on seropositivity, sporadic abortion, and stillbirth cases in livestock caused by Coxiella burnetii

BackgroundQ fever and toxoplasmosis are economically important zoonoses as they cause considerable losses in livestock (cattle, sheep and goats) and wildlife (antelopes, giraffes, lions, and cheetahs) through reproductive disorders such as abortions and stillbirths. Q fever and toxoplasmosis testing in South Africa is conducted by the Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR). However, both zoonoses are understudied and not monitored in South Africa as they are not considered controlled or notifiable diseases in the Animal Disease Act 35 of 1984. A retrospective study was conducted on Q fever (2007–2009) and toxoplasmosis (2007–2017) using diagnostic laboratory data at the ARC-OVR. Also, we report on sporadic abortion and stillbirth cases in livestock from diagnostic tissue samples submitted for Coxiella burnetii polymerase chain reaction (PCR) detection at the ARC-OVR.ResultsDuring 2007 to 2009, 766 animal samples were tested for C. burnetii antibodies and seropositivity was 0.9% (95%CI: 0.3–1.7) with sheep (1.9%; 95%CI: 0.6–4.4) having the highest seropositivity followed by cattle (0.7%; 95%CI: 0.09–2.6), while all goats (0.0%; 95%CI: 0.0–4.2) and wildlife (0.0%; 95%CI: 0.0–2.5) tested were negative. From 2007 to 2017, 567 sera were tested for T. gondii antibodies; overall seropositivity was 12.2% (95%CI: 9.6–15). Wildlife had highest seropositivity to T. gondii antibodies (13.9%; 95%CI: 9.0–19.7) followed by goats (12.9%; 95%CI: 9.2–17.4) and sheep (12.3%; 95%CI: 5.1–23.8) while seropositivity in cattle was 2.4% (95%CI: 0.06–12.9). Of 11 animals tested by C. burnetii PCR detection (2021–2022), 10 (91.0%) were positive. The amplicon sequences showed similarity to Coxiella burnetii strain 54T1 transposase gene partial coding sequence.ConclusionsWe have confirmed the occurrence of the causative agents of Q fever and toxoplasmosis in livestock and wildlife in South Africa, with data limitations. These zoonoses remain of importance with limited information about them in South Africa. This study provides baseline information for future studies on Q fever and toxoplasmosis in South African livestock and wildlife, as well other African countries. Due to limited data collection experienced in this study, it is recommended that improvements in data collection samples tested should include associated factors such as sex, age, and breed of the animals.

Seroprevalence of &lt;i&gt;Brucella&lt;/i&gt; infection in cattle and small ruminants in South Omo zone, southern Ethiopia

A cross-sectional study was conducted in selected districts of the South Omo Zone to estimate the seroprevalence of brucellosis and its associated risk factors. Additionally, the knowledge, attitude, and practices (KAP) of livestock keepers about the disease were also assessed. A total of 1349 sera samples were collected from 450 cattle and 899 small ruminants (450 goats and 449 sheep) kept under an extensive production system. Rose Bengal Plate Test was used for screening and ELISA as a confirmatory test for the detection of antibodies against Brucella species. Based on confirmatory tests, the overall seroprevalence of brucellosis was 2.2 % (95% CI: 1.1 – 4.1%) in cattle, 2.0% (95% CI: 0.9, 3.8%) in goats and 1.3% (95% CI: 0.5, 2.9%) in sheep with higher seropositivity in cattle compared to small ruminants. Seropositivity did not vary significantly (p&gt; 0.05) with agroecology, age, and sex groups in cattle. However, a higher seroprevalence of 2.7% was detected in male cattle compared to 1.6% for females. Seroprevalence was higher in small ruminants from the lowland agroecology (3.0%) than those from the midlands (0.8%). Study respondents had a low level of knowledge on brucellosis with only 43% of them having some information about the disease. Most of the respondents have routinely engaged in practices that can expose them to infections such as assisted delivery (65%), contact with after-birth materials (50%), and handling aborted materials (15%) without any protection. High consumption of unpasteurized dairy products (93%) such as raw whole milk and traditionally fermented dairy product is also common. This study provides information on the occurrence f brucellosis in major livestock species kept at cross-border marginal areas with limited disease information. The existence of various exposure practices implies the need for creating awareness among livestock keepers on general disease transmission and its zoonotic role.

Seroprevalence of Chlamydia abortus in Anestrous Cattle of Nawalpur and Chitwan District, Nepal

Chlamydia abortus are gram negative coccoid, obligate intracellular zoonotic bacteria responsible for abortion and other reproductive problems in dairy cattle. This leads to sub-fertility and infertility in cattle thereby causing significant economic losses to dairy farmers. However, the status of Chlamydia abortus in Nawalpur and Chitwan districts, which are the dairy pockets of Nepal, are poorly understood. The objective of this study was to determine the seroprevalence of antibodies to Chlamydia abortus in anestrous dairy cattle of Nawalpur and Chitwan districts in relatively low risk winter season. In total, 92 cattle serum (Nawalpur (n= 27) and Chitwan (n= 65) samples were collected from April 2018 to May 2019 and tested using a Chlamydia abortus specific indirect ELISA kit to evaluate the seropositivity status of cattle. Results showed that only 2 (2.17%) cattle were seropositive for Chlamydia abortus. Both the positive cattle were Jerseys from Nawalpur area with a history of abortion. The ages of the seropositive cattle were 3 and 4 years. In conclusion, there was a low seroprevalence of C. abortus in dairy cattle of Nawalpur and Chitwan districts. The presence of this bacterium suggests that it is likely to be a cause of unidentified abortion in dairy cattle in Nepal. We suggest screening dairy animals for C. abortus infection to minimize this risk.

The Control Program of Brucellosis by the Iranian Veterinary Organization in Industrial Dairy Cattle Farms.

Brucellosis is a zoonotic infection in livestock that induces a major public health concern in developing countries, including Iran. Despite the efforts of the Iranian veterinary organization (IVO) to control brucellosis, it is still prevalent in domestic animals. In this regard, the present study aimed to evaluate the efficiency of the control strategy used by the IVO in infected herds on serological, cultural, and molecular methods. For this purpose, blood specimens were sampled from a total of 8750 vaccinated dairy cattle in two Brucella-infected farms. These farms were recognized as positive for Brucella by a screening program. Sera were evaluated by the Rose Bengal Plate Test and Wright test analysis. Positive dairy cattle were slaughtered under IVO supervision. The remaining cattle were evaluated every 3 weeks and positive animals were slaughtered. This procedure continued until the remaining animals revealed three successive negative responses in serological tests. Several lymph nodes and milk samples were collected from 164 seropositive cattle and subjected to bacterial isolation and confirmation by Bruceladder-polymerase chain reaction. Brucella melitensis biovar 1 and RB51 vaccine strains were recovered from milk and lymph node samples, respectively. Shedding of B. melitensis in the milk of vaccinated cows is a serious problem resulting in the further spread of brucellosis. The policy of "test and slaughter" performed on infected dairy cattle farms showed their usefulness for the control of brucellosis outbreaks. For the uncontrolled spread of brucellosis in Iran, effective control of bovine brucellosis required several serological surveillances to identify infected herds, eradication of the reservoirs, and vaccination of young heifers with RB51.

Prevalence and risk factors of Q fever (Coxiella burnetii) in cattle on farms of Limpopo province, South Africa.

Q fever in animals and humans and its economic and public health significance has been widely reported worldwide but in South Africa. There are few studies on the prevalence of this zoonosis and its associated risk factors in South African livestock. Therefore, a cross-sectional study was conducted to determine the seroprevalence, molecular prevalence, and risk factors associated with C. burnetii in cattle on farms in South Africa's Limpopo province. Out of 383 cattle tested for antibodies, the overall seroprevalence was 24.28%. Herd size of >150 (OR: 9.88; 95%CI: 3.92-24.89; p < 0.01) remained associated with C. burnetii seropositivity in cattle. For PCR detection, targeting IS1111 fragment, cattle with no abortion history (OR: 0.37; 95%CI: 0.18-0.77; p < 0.01) and herd size of >150 (OR: 3.52; 95%CI: 1.34-9.24; p < 0.01) remained associated with C. burnetii positivity. The molecular prevalence in sheath scrapings and vaginal swabs by IS1111 PCR was 15.67%. Cohen's kappa agreement test revealed a fair agreement between the PCR and ELISA results (k = 0.40). Sequence analysis revealed that the amplicons had similarities to the C. burnetii transposase gene fragment, confirming the presence of the pathogen. The higher seroprevalence than molecular prevalence indicated a past C. burnetii infection, no bacterial shedding through vaginal mucus in cows, or preputial discharge in bulls. Similarly, the detection of C. burnetii by PCR in the absence of antibodies could be partly explained by recent infections in which antibodies have not yet been produced against the bacteria, or the level of these antibodies was below the detectability threshold. The presence of the pathogen in cattle and the evidence of exposure, as shown by both PCR and ELISA suggests an active circulation of the pathogen. This study demonstrated that C. burnetii is widespread in the study area and that a herd size of >150 is associated with C. burnetii seroprevalence and molecular prevalence.

Serological and haemato-biochemical insights into bovine leukosis in dairy cattle in D.I. Khan, Pakistan

Bovine leukosis is an economically important disease of dairy cattle caused by the bovine leukaemia virus (BLV). The study aimed to determine the seroprevalence, haemato-biochemical effects, and risk factors pertinent to the prevalence of bovine leukosis in Holstein–Friesian purebred dairy cattle in the D.I. Khan region of Pakistan. A total of 192 sera were assayed using an enzyme-linked immunosorbent assay. Overall, 31.3% (60/192) cattle were detected as seropositive. There was a marked increase in total leukocyte count (11.29 ± 0.48×103/μl), lymphocytes (5.73 ± 0.42%), monocytes (0.81 ± 0.06%), haemoglobin (11.09 ± 0.46 g/dl), red blood cells (7.23 ± 0.37 ×106/μl), and packed cell volume (31.75 ± 1.48%) in seropositive cattle. Serum biochemical parameters in seropositive cattle showed a marked increase in the liver enzymes, alanine transaminase (24.25 ± 1.03 U/l) and aspartate aminotransferase (49.33 ± 3.31 U/l), with a marked decrease in glutathione peroxidase (1365.63 ± 12.03 (U/l) and superoxide dismutase (2.14 ± 0.13 U/ml) activity. A significant association of age, pregnancy, breeding method, milk yield, and health status of seropositive animals with bovine leukosis was also recorded. The prevalence was higher in animals which were older, pregnant, artificially inseminated, low milk producers, and had a history of ailments. The current study found that bovine leukosis virus could cause changes in internal homeostasis, oxidative stress, and liver dysfunction, all of which should be considered during a control regimen. It was concluded that bovine leukosis was moderately prevalent in the D.I. Khan region in Pakistan.