Seropositive Sheep Research Articles

Demography of Q fever seroprevalence in sheep and goats in The Netherlands in 2008

At the end of 2007, the first year of what later turned out to be one of the largest Q fever outbreaks in the world with ultimately almost 3500 human patients notified in three years time, dairy goats were suspected to be the possible cause. However, current information on the Q fever prevalence in small ruminants in The Netherlands was lacking.A serological survey, using an indirect ELISA, was carried out in 15,186 sheep and goats in The Netherlands in 2008. In total, 2.4% (95% CI: 2.2–2.7) of the sheep and 7.8% (95% CI: 6.9–8.8) of the goats was seropositive for antibodies against Coxiella burnetii. In 14.5% (95% CI: 12.5–16.5) of the sheep flocks and 17.9% (95% CI: 14.2–21.5) of the goat herds at least one seropositive animal was found. In sheep flocks with at least one seropositive sheep, the within herd seroprevalence was 14.8% (95% CI: 12.6–17.0). In goat herds with at least one seropositive goat, the within herd seroprevalence was 29.0% (95% CI: 24.6–33.3).The seropositive sheep were equally distributed across the country. The seroprevalence in goats in the south-eastern part of The Netherlands, the area where most of the human Q fever cases were notified, was significantly higher than the seroprevalence in goats in the rest of The Netherlands. Dairy sheep and dairy goats had a significantly higher chance of being seropositive than non-dairy sheep and goats. During pregnancy and in the periparturient period, small ruminants tested significantly more often seropositive than in the early- or non-pregnant period.The seroprevalence as well as the true prevalence among small ruminants in The Netherlands were lower than prevalences reported elsewhere. The seroprevalence among sheep was also lower than reported in an earlier Dutch study in 1987. The Q fever seroprevalence was highest in pregnant and periparturient dairy goats in the south-eastern part of The Netherlands, which coincides with the region with the highest human incidence of Q fever.

Prevalence ofCoxiella burnetiiin Hungary: Screening of Dairy Cows, Sheep, Commercial Milk Samples, and Ticks

Q fever is an important zoonotic disease caused by Coxiella burnetii. There are few reliable data about C. burnetii infection available. The aim of this study was to assess the importance and potential infectious sources of Q fever in Hungary. A total of 215 milk samples (10 individual samples from each herd and 1 bulk tank milk sample from each cattle herd), and 400 serum samples (20 from each herd) were tested from 15 dairy cattle herds and 5 sheep flocks located in different parts of Hungary. The study found 19.3% (58/300) and 38.0% (57/150) seropositivity in cattle, and 0% (0/100) and 6.0% (3/50) seropositivity in sheep, by complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA), respectively. C. burnetii DNA was detected by IS1111 element-based TaqMan real-time polymerase chain reaction (PCR) in 8.7% (13/150) of individual dairy cow milk samples, 4.0% (2/50) of individual sheep milk samples, and 66.7% (10/15) of dairy bulk tank milk samples. Samples taken from nine different commercially-available pasteurized cow milk products from different Hungarian producers were also tested for the presence of C. burnetii DNA, and eight of these samples were found to be positive (88.9%). The real-time PCR examination of 5402 ixodid ticks collected from different parts of the country yielded negative results. Knowledge of the true prevalence of Q fever is crucial for policymakers involved in evidence-based decision making.

Caracterização epidemiológica e fatores de risco associados à leptospirose em ovinos deslanados do semiárido brasileiro

Este trabalho teve como objetivo determinar a prevalência de rebanhos ovinos positivos (focos) e de animais soropositivos para leptospirose na região semiárida do Estado da Paraíba, bem como identificar fatores de risco. Foram colhidas amostras de sangue de 1.275 animais procedentes de 117 rebanhos em 19 municípios da mesorregião do Sertão, Estado da Paraíba. Para o diagnóstico sorológico da leptospirose foi utilizado o teste de soroaglutinação microscópica (SAM), com 24 sorovares de Leptospira spp. como antígenos. Um rebanho foi considerado positivo quando apresentou pelo menos um animal soropositivo. Das 117 propriedades utilizadas 33 (28,20%) apresentaram pelo menos um animal soropositivo, e dos 1.275 animais 69 (5,41%) foram soropositivos, com títulos variando de 100 a 3200. O sorovares reagentes foram Autumnalis (49,30%), Andamana (27,53%), Sentot (17,39%), Whitcomb (4,34%) e Australis (1,44%). Possuir mais de 48 animais no rebanho (odds ratio = 2,26; IC 95% = 1,33 -5,07; p = 0,021) e participação em exposições (odds ratio = 9,05; IC 95% = 0,96 - 85,71; p = 0,055) foram identificados como fatores de risco. Sugere-se a necessidade de estudos acerca do isolamento do agente, da caracterização de sua patogenicidade e do seu impacto econômico nos rebanhos ovinos da região, bem como recomenda-se maior controle sanitário nas aglomerações de animais.

Seroprevalence and risk factors for Neospora caninum in sheep in the state Minas Gerais, southeastern Brazil

The aim of this study was to determine the prevalence and risk factors associated with infection due to Neospora caninum in serum samples from 488 sheep originating from 63 farms in 63 municipalities distributed across eight of the twelve mesoregions of the state Minas Gerais, southeastern Brazil. For detection of N. caninum the sheep serum samples were subjected to the indirect fluorescence antibody test (IFAT≥50). To identify the risk factors associated with infection due to N. caninum a questionnaire was filled out for each herd by interviewing, the individual responsible for the herd, demanding information on the general characteristics of the property. Sixty-four sheep sera (13.1%; 95% CI=10.3–16.4) presented IgG-specific anti-N. caninum antibodies with the following titers: 50 (49; 76.6%), 100 (7; 10.9%), 200 (4; 6.2%), 400 (3; 4.7%) and 800 (1; 1.6%). The prevalence of infected sheep per mesoregion ranged from 0 to 28.1%. Out of the 63 farms sampled, 31 (49.2%; 95% CI=36.4–62.1) presented at least one seropositive sheep. No significant association was found between the presence of anti-N. caninum antibodies and the risk factors evaluated on the farms, except for the mesoregion variable (p=0.004; OR=0.429; CI95%=0.182–1.008). These results indicate that there is a need for additional research to define the epidemiological importance of this parasite as a cause of reproductive problems in sheep herds in Minas Gerais.

Detection of Mycobacterium avium subsp. paratuberculosis in intestinal and mammary tissues and in lymph nodes of sheep with different techniques and its relationship with enteric lesions

Paratuberculosis is a widespread disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). For long time the infection has been believed as confined to the intestine. Disseminated infection in ruminants with MAP has gained more interest in recent years. In this study the histological lesions, the distribution of MAP in intestinal and mammary tissues of seropositive sheep and the sensitivity of direct diagnostic tests are evaluated. Histopathological lesions were observed in the proximal jejunum, distal jejunum and ileum of 19 sheep. Types 3b and 3c lesions were observed. Sheep with subclinical infection had type 3c ileal lesions, while clinically infected animals had mainly type 3b ileal lesions (p<0.05). Ziehl–Neelsen (ZN) staining was more sensitive for detecting acid-fast bacilli in type 3b intestinal lesions than in type 3c (p<0.05). Immunohistochemistry (IHC) was more sensitive than ZN staining in detecting infected intestinal samples (p<0.05). PCR was the most sensitive technique in detecting MAP in both intestinal and extra-intestinal samples (p<0.05). MAP was mainly observed in mammary tissues of sheep with type 3b intestinal lesions, although these findings were not statistically significant (p>0.05). The number of MAP in the intestine might influence the clinical course and the local histopathological lesions, but probably further factors contribute to the discrimination between local and general infection.

Seroprevalence of Toxoplasma gondii Infection in Domestic Sheep in Durango State, Mexico

The seroprevalence of Toxoplasma gondii infection in sheep (Ovis aries) in northern Mexico is largely unknown. Antibodies to T. gondii were determined in serum samples from 511 sheep from 8 farms in Durango State, Mexico, using the modified agglutination test (MAT). Sheep were raised in 3 geographical regions, i.e., mountainous (n = 68), semi-desert (n = 132), and valley (n = 311). Overall, T. gondii antibodies were found in 77 (15.1%) of 511 sheep, with MAT titers of 1∶25 in 27, 1∶50 in 10, 1∶100 in 11, 1∶200 in 11, 1∶400 in 8, 1∶800 in 3, 1∶1,600 in 4, and 1∶3,200 in 3. The seroprevalence of T. gondii infection increased significantly with age, indicating post-natal transmission. In contrast, gender, breed, flock size, and geographic region did not significantly influence the seroprevalence. Seropositive sheep were found in 7 of 8 farms sampled. This is the first report of T. gondii infection in sheep in Durango State, Mexico. Results indicate that infected sheep are probably an important source of T. gondii infection for humans in Durango State.

Seroprevalence of Toxoplasma gondii in Pigs, Sheep, Goats, and Cattle from Grenada and Carriacou, West Indies

Prevalence of Toxoplasma gondii infection in pregnant women in Grenada is considered high. Little is known of the epidemiology of T. gondii infection in Caribbean Islands. Serum samples of 750 food animals in Grenada and Carriacou were tested for antibodies to T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT, 1∶25 or higher) were found in 23.1% of 247 pigs, 44.1% of 204 sheep, 42.8% of 180 goats, and 8.4% of 119 cattle. Seroprevalence increased with age, indicating postnatal acquisition of T. gondii. Antibody titers of 1∶200 or higher were present in 65 of 90 seropositive sheep, 61 of 77 seropositive goats, and 23 of 57 seropositive pigs. However, none of the cattle had a MAT titer of 1∶200, suggesting that bovines are a poor host for T. gondii. Results indicate that pigs, sheep, and goats could be important sources of T. gondii infection if their meat is consumed undercooked.

Corynebacterium Pseudotuberculosis Secreted Antigen-Induced Specific Gamma-Interferon Production by Peripheral Blood Leukocytes: Potential Diagnostic Marker for Caseous Lymphadenitis in Sheep and Goats

In the current study, the applicability of the quantification of gamma interferon (IFN-γ) levels for the detection of animals infected with Corynebacterium pseudotuberculosis and for determining caseous lymphadenitis (CLA) clinical status was evaluated. Peripheral blood leukocytes were collected from CLA nonendemic areas animals, from CLA seropositive animals without clinical signs of the disease, and from seropositive animals presenting CLA clinical signs. The leukocytes were stimulated with C. pseudotuberculosis-secreted antigens that were concentrated by the three-phase partitioning technique. An ovine IFN-γ enzyme-linked immunosorbent assay was used to quantify IFN-γ production. Goats and sheep with CLA had higher IFN-γ levels than uninfected seronegative animals. Leukocytes from sheep with CLA chronic abscesses produced higher IFN-γ levels when compared with seropositive sheep without CLA clinical signs, but this difference was not significant in goats. The sensitivity of the assay was 55.8% and 56%, whereas the specificity was 100% and 93%, for goats and sheep, respectively. In conclusion, IFN-γ is a potential marker for the determination of CLA infection status in small ruminants; however, further research is needed to improve assay sensitivity.

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes

Toxoplasmosis is the major parasitic disease affecting sheep. It is important for veterinary medicine, animal science and public health since it causes reproductive and economic losses in the herd, as well as damaging human health due to consumption of contaminated meat and milk, which can facilitate zoonotic transmission. Detection of Toxoplasma gondii in ovine milk and lack of data in the literature describing differentiation between acute and chronic disease for this species stimulated the elaboration of the present research project. To achieve the aim of this study, the animals were allocated to two groups of 20 ewes each, of which group 1 was composed of animals with positive serology and group 2 with negative serology. Acute and chronic stages of the disease were differentiated by modified direct agglutination test (MAT), in which antigens were fixed with formalin (MAT-AF) and methanol (MAT-AM). The parasite was detected in milk by polymerase chain reaction (PCR), and the molecular identity of the amplified products was confirmed by sequencing. The serological results indicated that sheep had a chronic infection profile. T. gondii DNA was detected in seven milk samples from five seropositive sheep, and twice in milk of two sheep. Sequences of species shared 97–100% identity with T. gondii. These findings allowed the hypothesis that the peripartum period may also lead to the resurgence of tissue T. gondii tachyzoites cysts which can circulate again and be excreted in the milk. This study used sheep naturally infected with T. gondii as a prerequisite for further investigations on the possible participation of this species in toxoplasmosis epidemiology and as a potential transmission route related to consumption of milk from infected sheep.

Bayesian estimation of the true prevalence of Mycobacterium avium subsp. paratuberculosis infection in Cypriot dairy sheep and goat flocks

We estimated the prevalence of Mycobacterium avium subsp. paratuberculosis (MAP) infected sheep and goats, older than 2 years, reared in the region effectively controlled by the Government of the Republic of Cyprus, in September 2005. The sera collected from 8011 animals (3429 sheep and 4582 goats) from 83 flocks, non-vaccinated against MAP, were examined for antibodies with a commercially available enzyme linked immunosorbent assay (Pourquier ® paratuberculosis antibody screening ELISA). The true prevalence of MAP infection was calculated, in a Bayesian framework, separately in sheep and goats, with models that adjusted for the misclassification of animals because of the imperfect accuracy of the ELISA. The within-flock mean seroprevalence in sheep and goats was 9.9% (95% CI: 8.9; 10.9%) and 7.9% (7.2; 8.7%), respectively. There was at least one seropositive sheep in 52% (38; 66%) of flocks with sheep and one seropositive goat in 50% (39; 62%) of flocks with goats. Within the seropositive flocks the mean seroprevalence was 12.1% (10.9; 13.4%) and 10.3% (9.3; 11.4%) in sheep and goats, respectively. The calculated mean true prevalence of infected sheep and goats was 15.0 and 11.1%, respectively. There was at least one infected sheep in 60.8% (95% credible interval: 42.3; 78.8%) and at least an infected goat in 48.6% (30.4; 68.5%) of the flocks. In the infected flocks, the mean within flock true prevalence of infection in sheep and goats was estimated at 24.6% (16.3; 33.3%) and 23.1% (15.5; 33.6%), respectively.

Seroprevalence survey for Salmonella Abortusovis infection in Swiss sheep flocks

Between 1976 and 2003, no infections with Salmonella Abortusovis had been officially recorded in Switzerland. Since then, however, several sheep flocks were infected and suffered massive fetal losses suggesting a re-emergence of the disease. Therefore, the aim of this study was to assess the epidemiological situation of S. Abortusovis infection in sheep in this country. A representative serum sample collected in 2007 in the context of certifying Brucella freedom included sera from 578 flocks with a total of 8426 sheep from all regions in Switzerland and the Principality of Liechtenstein. Sera were tested by ELISA for the presence of antibodies specific for S. Abortusovis. The cantonal seroprevalence was estimated at the sheep as well as the flock-level by taking into account (a) all flocks with one or more seropositive sheep (Flock 1+) and (b) only the flocks with two or more seropositive sheep (Flock 2+). Flocks with seropositive sheep were found throughout the country with an overall sheep-level prevalence of 1.7%. At the flock-level, overall prevalences of 16.3% and 5.0% were found for Flock 1+ and Flock 2+ definitions, respectively. Significant sheep-level clusters were located in the cantons of Bern, the Valais and Graubünden, while significant flock-level clusters (Flock 1+ and Flock 2+) were located in the canton of Graubünden only. Our results indicate that exposure of Swiss sheep flocks to S. Abortusovis is wide-spread.

Toxoplasma gondii in wild cervids and sheep in Finland: North-south gradient in seroprevalence

A nationwide seroepidemiological study was conducted to estimate the prevalence of Toxoplasma gondii in selected wild and domestic ruminants in Finland. Serum samples from 1367 game cervids collected during the hunting season in 2008-2009 and 1940 sheep sera collected in 2008 were screened with a commercial direct agglutination test at a serum dilution of 1:40. T. gondii-specific IgG antibodies were detected in 116 (9.6%) of 1215 moose (European elk, Alces alces), 36 (26.7%) of 135 white-tailed deer (Odocoileus virginianus), 3 (17.6%) of 17 roe deer (Capreolus capreolus), and 477 (24.6%) of 1940 domestic sheep. Seropositive sheep were found in 74 (76.3%) of the 97 flocks examined. The odds of seropositivity in the adult moose was 2.9 times higher than the odds in calves; in white-tailed deer, the odds ratio was 3.2. The male moose had a significantly lower seroprevalence than the female, whereas the seroprevalence in the male white-tailed deer was higher than in the female; the odds ratios were 0.6 and 2.5, respectively. A clear geographical gradient in the seroprevalence was revealed in moose and sheep. The seroprevalences were lowest (1.6 and 8.6%, respectively) in the north and highest (24.6 and 36.4%, respectively) in the south-western regions, and ranged between these values in the other regions. In fact, the seroprevalence in moose from the south-west was not significantly different from the prevalence in white-tailed deer from the same area. Thus, the Finnish wild cervids and sheep are commonly exposed to T. gondii, especially in the southern part of the country.

Mosquitoes and Mosquito-Borne Arboviruses in the Qinghai-Tibet Plateau—Focused on the Qinghai Area, China

An investigation was conducted to identify the distribution of mosquitoes and mosquito-borne arboviruses in the Qinghai-Tibet Plateau, China from July to August in 2007. A total of 8,147 mosquitoes representing six species from three genera (Aedes, Culex, and Anopheles) were collected in three locations (Geermu city, altitude of 2,780 m; Xining city, 2,200 m; Minhe county, 1,700 m). Six virus isolates were obtained including Tahyna virus (TAHV), Liaoning virus, and Culex pipiens pallens Densovirus. A serosurvey showed immunoglobulin G antibodies by immunofluorescence assay (IFA) against TAHV in residents of all three locations. The IFA-positive human samples were confirmed by 90% plaque-reduction neutralization tests (PRNT(90)) against TAHV with titers ranging from 1:20 to 1:10,240. In addition, TAHV seropositive cows, sheep, and swine were found in these locations. This investigation represents the first isolation of TAHV from Ae. (Och.) detritus and the first evidence of TAHV infection in residents and livestock in the Qinghai-Tibet Plateau.

Risk Factors Associated with Neospora caninum Seropositivity in Sheep from the State of Alagoas, in the Northeast Region of Brazil

The aim of this study was to identify risk factors associated with Neospora caninum seropositivity in sheep from the State of Alagoas, in the northeast region of Brazil. Twenty-six herds were selected, and blood samples were collected from 343 animals > 6-mo-old. The indirect fluorescent antibody test (IFAT) was used for serological diagnosis of N. caninum infection. Epidemiological questionnaires were applied for each herd to identify the risk factors associated with infection. Thirty-three (9.6%) animals tested positive for anti- N. caninum IgG antibodies, with titers ranging from 1 ratio 50 to 1 ratio 1,600. Fourteen herds (53.8%) presented at least 1 seropositive animal. Risk factors identified were property size <or= 30 ha (odds ratio = 7.23; 95% CI = 1.99-26.49) and source of water (wells + municipal + water courses) (odds ratio = 4.76; 95% CI = 1.23-18.47). This is the first ezootiological study of N. caninum infection in sheep to be carried out in the State of Alagoas. Preventive measures focusing primarily on water treatment should be taken to reduce the risk of infection by N. caninum .

Effects of housing on the incidence of visna/maedi virus infection in sheep flocks

The incidence of seroconversion to visna/maedi virus (VMV) infection and its relationship with management and sheep building structure was investigated in 15 dairy sheep flocks in Spain during 3-7years. Incidence rates were 0.09 per sheep-year at risk in semi-intensive Latxa flocks and 0.44 per sheep-year at risk in intensive Assaf flocks and was greatest for the one year old Assaf replacement flock. Separate multivariable models developed for replacement and adult flocks indicated that in both cases seroconversion was strongly associated to direct contact exposure to infected sheep and to being born to a seropositive dam. The latter effect was independent of the mode of rearing preweaning and the risk of seroconversion was similar for sheep fed colostrum and milk from a seropositive or a seronegative dam. These results are further evidence of the efficiency of horizontal VMV transmission by close contact between sheep and also suggest a inheritable component of susceptibility and resistance to infection. In contrast, indirect aerogenous contact with seropositive sheep was not associated with seroconversion as evidenced in replacement sheep housed in separate pens in the same building as adult infected sheep for one year. Consequently, VMV may not be efficiently airborne over short distances and this is important for control of infection. Moreover, there was no relationship between seroconversion and shed open areas. The latter could be related to having examined few flocks in which high infection prevalence dominated the transmission process while ventilation, may depend on a variety of unrecorded factors whose relationship to infection needs to be further investigated.

Caseous lymphadenitis in sheep flocks of the state of Minas Gerais, Brazil: Prevalence and management surveys

Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis, which is a serious, economically important problem for sheep production. We examined the seroprevalence of infection by C. pseudotuberculosis and possible risk factors associated with caseous lymphadenitis in sheep herds of the state of Minas Gerais, Brazil. Samples were collected from 642 sheep from 97 farms. Sera of all of the sheep were tested with ELISA for antibodies against C. pseudotuberculosis. A questionnaire was applied to gather data on the farm, the sheep herd, the farmer, and individual animal data (breed, sex and age). This is the first sero-epidemiological survey for caseous lymphadenitis in sheep herds in Minas Gerais. We found a high real prevalence, much higher than that suggested from information obtained with the questionnaire, which points to the scarcity of vaccination against caseous lymphadenitis in the sample evaluated. Only a small proportion of the farmers declared that cases of this disease were present in their flocks. The frequency of seropositive sheep varied significantly with breed ( χ 2 test, P = 0.021). Age group also significantly affected the percentage of seropositivity ( χ 2 test, P = 0.049), the highest frequency being found in adult animals (more than 12 months old), when compared to the 5–12 months old group ( χ 2 test, P = 0.021). The prevalence of infection with C. pseudotuberculosis in sheep in the state of Minas Gerais was estimated to be 70.9% (95% confidence interval (CI): 64.7–77.0%) and the prevalence of infected flocks being 95.9% (95% CI: 89.8–98.9%). We concluded that C. pseudotuberculosis infection is widely disseminated in sheep flocks in Minas Gerais and that caseous lymphadenitis control and eradication programs are necessary in this state.

Visna/maedi virus serology in sheep: Survey, risk factors and implementation of a successful control programme in Aragón (Spain)

A serological survey of Visna/maedi virus (VMV) infection involving 274,048 sheep from 554 flocks was undertaken during 2002-2007 in Aragón, North-East Spain. One hundred and two of these flocks enrolled in a VMV control programme to reduce seroprevalence by selecting replacement lambs from seronegative dams and gradual culling of seropositive sheep. Twenty-five flocks were also visited to collect flock management and housing data. All study flocks had seropositive animals and 52.8% of animals tested were seropositive. Among flocks that joined the control programme 66 adopted the proposed measures and reduced seroprevalence significantly by between 26.1% and 76.9% whereas the remaining 36 flocks did not apply the measures and seroprevalence significantly increased. Seroprevalence increased with flock size and the number of days the sheep were housed, and decreased with increasing weaning age and shed open area, suggesting a reduced risk of VMV infection in sheep associated with better ventilation. At the end of the period, 24 flocks were certified as VMV-controlled with a seroprevalence <5%, and seven as VMV-free with 0% seroprevalence. These are the first officially recognised VMV-free flocks in Spain and represent a nucleus of VMV-free replacement animals for other flocks. Moreover, they are evidence of the possibility of eliminating VMV infection without resorting to whole-flock segregation or culling of seropositive sheep.

Investigations into the Cause of Foot-and-Mouth Disease Virus Seropositive Small Ruminants in Cyprus During 2007

In 2007, serological evidence for foot-and-mouth disease (FMD) infection was found as a result of differential diagnostic testing of Cypriot sheep suspected to be infected with bluetongue or contagious ecthyma. Seropositive sheep and goats were subsequently uncovered on ten geographically clustered flocks, while cattle and pigs in neighbouring herds were all seronegative. These antibodies were specific for serotype-O FMD virus, reacting with both structural and non-structural (NS) FMD viral proteins. However, no FMD virus could be recovered from the seropositive flocks. FMD had not been recorded in Cyprus since 1964 and there has been no vaccination programme since 1984. Since all the seropositive animals were at least 3 years old and home-bred, it was concluded that infection had occurred approximately 3 years previously had passed un-noticed and died out spontaneously. It therefore appears that antibodies to FMD virus NS proteins can still be detected around 3 years after infection of small ruminants, but that virus carriers cannot be detected at this time. This unusual situation of finding evidence of historical infection in a FMD-free country caused considerable disruption and alarm and posed questions about the definition of what constitutes a FMD outbreak.

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ⩾ 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.

Identification of Leptospira spp. carriers among seroreactive goats and sheep by polymerase chain reaction

Few studies were conducted on the diagnosis and control of small ruminants’ leptospirosis. Thirteen goat herds and seven sheep flocks located in the state of Rio de Janeiro, Brazil, were screened for leptospirosis. From the three herds and three flocks with greatest seroreactivity by MAT (Microscopic Agglutination Test), 19 and 40 seropositive goats and sheep, respectively, were selected, and urine samples were collected for bacteriology and PCR. For both species of animals, the most prevalent reactions were due to serogroups Sejroe and Shermani. Although leptospires were observed by darkfield microscopy in eight samples, pure isolates were obtained by bacteriological culture from only two samples. However, twelve urine samples (six goats and six sheep) were positive by PCR. Based on these findings, we consider that the combined use of MAT as a screening test followed by urine PCR for the direct detection of Leptospira spp. DNA was adequate for the identification of carrier animals among goats and sheep. These are valuable tools for the control of leptospirosis in small ruminants.