Transcription of non-classic major histocompatibility complex (MHC) class I in the bovine placenta throughout gestation and after Brucella abortus infection.

Transcription of non-classical major histocompatibility complex class I (MHC-I) was assessed in the bovine placenta throughout gestation. Additionally, the effect of Brucella abortus infection on expression of non-classical MHC-I was also evaluated using a chorioallantoic membrane explant model of infection. The non-classical MHC-I genes MICB and NC3 had higher levels of transcription in the intercotyledonary region when compared to the placentome, which had higher levels of transcription at the second trimester of gestation. NC1 and classical MHC-I had very low levels of transcription throughout gestation. Trophoblastic cells of B. abortus-infected chorioallantoic membrane explants had an increase in transcription of non-classical MHC-I at 4h post infection. Therefore, this study provides an analysis of non-classical MHC-I transcription at different stages of gestation and different placental tissues, and during B. abortus infection. These findings provide additional knowledge on immune regulation in placental tissues, a known immune-privileged site.

Brucellosis, genital campylobacteriosis and other factors affecting calving rate of cattle in three states of Northern Nigeria.

BACKGROUND: Reproductive diseases limit the productivity of cattle worldwide and represent an important obstacle to profitable cattle enterprise. In this study, herd brucellosis and bovine genital campylobacteriosis (BGC) status, and demographic and management variables were determined and related to predicted calving rate (PrCR) of cattle herds in Adamawa, Kaduna and Kano states, Nigeria. Serum samples, preputial scrapings, questionnaire data, trans-rectal palpation and farm records were used from 271 herds. The Rose-Bengal plate test and competitive enzyme-linked immunosorbent assay were used for Brucella serology and culture and identification from preputial samples for BGC. A herd was classified as positive if one or more animals tested positive. The PrCR was determined as the number of calvings expected during the previous 6 and next 6 months as a percentage of the number of postpubertal heifers and cows in the herd. A multilevel linear regression model was used to estimate the herd-level effect of Brucella abortus seropositivity, Campylobacter fetus infection and other factors on calculated PrCR. RESULTS: The reproductive performance of the cattle herds was generally poor: Only 6.5% of the nursing cows were pregnant and 51.1% were non-pregnant and acyclic; the mean annual PrCR was 51.4%. Brucella abortus and C. fetus infection of herds were independently associated with absolute reduction in PrCR of 14.9% and 8.4%, respectively. There was also a strong negative association between within-herd Brucella seroprevalence and PrCR. Presence of small ruminants, animal introduction without quarantine and the presence of handling facilities were associated with lower PrCR, whereas larger herd size, supplementary feeding, routine mineral supplementation and care during parturition were associated with higher PrCR. CONCLUSIONS: Brucellosis and BGC may be largely responsible for the poor reproductive performance of indigenous Nigerian cattle. Farmer education and measures to improve the fertility of cattle herds are suggested.

Was the French clinical surveillance system of bovine brucellosis influenced by the occurrence and surveillance of other abortive diseases?

The bovine brucellosis clinical surveillance system implemented in France aims to detect early any case of bovine brucellosis, a disease of which the country has been declared free since 2005. It relies on the mandatory notification of every bovine abortion. Following the spread of the Schmallenberg virus (SBV) in France in 2012 and 2013, and the implementation in 2012 of a clinical surveillance programme of Q fever based on abortion notifications in ten pilot départements, our objective was to study whether these two events influenced the brucellosis clinical surveillance system. The proportion of notifying farmers was analyzed over each semester from June 1, 2009 to June 30, 2013 according to the size and production type of herds, SBV status of départements and the implementation of the Q fever surveillance. Our analysis showed a slight increase in the proportion of notifying farmers as départements became infected by SBV, and after the implementation of Q fever surveillance (during the first semester of 2013). These variations might be explained by an increase in abortion occurrence (congenital deformities in newborns, due to SBV) and/or by an increase in farmers' and veterinarians' awareness (due to the spread of SBV and the implementation of the Q fever surveillance). These results highlight the difficulties in interpreting variations in the proportion of notifying farmers as a consequence of an increase in abortion occurrence. As bovine abortion surveillance can play an important role in the early warning for several diseases, there is a need to explore other ways to monitor abortions in cattle, such as syndromic surveillance using the dates of artificial insemination or calving data.

Neospora caninum versus Brucella spp. exposure among dairy cattle in Ethiopia: a case control study.

This case-control study aimed at assessing the relative association of Neospora caninum and Brucella species exposure with reproductive disorders. The study was carried out between October 2011 and June 2012 on 731 dairy cows sampled from 150 dairy farms in selected 17 conurbations of Ethiopia. Two hundred sixty-six of the cows were categorized as cases based on their history of abortion or stillbirth while the remaining 465 were controls. The presence of antibody to N. caninum was screened using indirect ELISA, while Brucella spp. exposure was assayed serially using Rose Bengal Plate Test and Complement Fixation Test. Exposure to N. caninum was more frequently observed among cases (23.8%) than controls (12.7%), while no significant difference (p > 0.05) was noted for Brucella exposure between the two groups. Moreover, the proportion of cows with disorders like retention of fetal membrane, endometritis and increased inter-calving period were significantly higher (p < 0.05) among Neospora seropositive cows. In conclusion, the finding discloses the strong association of N. caninum with reproductive disorders compared to Brucella spp. exposure. However, neither N. caninum nor Brucella spp. could explain the majority (73.2%) of the reported abortions and stillbirths in cattle. Hence, this observation underscores the need for more intensive investigation on the identification of causes of the aforementioned disorders in dairy cattle of Ethiopia.

Milk yield and reproductive performance of brucellosis-vaccinated but seropositive Holstein cows.

The aim of this research was to study if seropositivity for brucellosis in vaccinated cows against this disease hampers reproductive performance and milk production in high-yielding Holstein cows. For this purpose 1,026 healthy cows and 372 cows seropositive for brucellosis were enrolled in this study. Cows positive to card test and subsequently to the rivanol test were further subjected to the radial immunodiffusion (RID) test. It was found that only 11% of the presumably infected cows by brucellosis screening tests were really infected with this disease. The reproductive performance of the group of cows with 11% Brucella-infected animals was not impaired; overall pregnancy rate did not differ between seropositive and healthy cows (30.9 vs. 29.6%). The abortion rates were similar between seropositive cows (5.3%) and seronegative animals (6.9%). Cows in the herd with 11% Brucella-infected animals produced significantly more milk than unaffected cows over a 305-day lactation (10,684 ± 1,720 vs. 10,345 ± 1,736; mean ± SD; P < 0.05). It was concluded that in dairy herds vaccinated against brucellosis with both 19 and RB51 strains, supplemental tests such as RID need to be conducted on all reactors in order to maintain diagnostic accuracy. These results also indicate that 11% animal prevalence of brucellosis did not exert a detrimental effect on 305-day milk yield and reproductive performance in high milk-yielding Holstein cows.

Brucellosis seroprevalence in Bali cattle with reproductive failure in South Sulawesi and Brucella abortus biovar 1 genotypes in the Eastern Indonesian archipelago.

BACKGROUND: Brucellosis is a major cause of infertility and reproductive failure in livestock. While cattle in the Eastern Indonesian archipelago suffers from reproductive problems information on bovine brucellosis in the region is fragmentary. The control of brucellosis requires a major and prolonged effort and confirmation of the infection by isolation with detailed knowledge of the spread of the infection is essential when planning a control program. RESULTS: Serological investigation of Brucella infection in beef cattle tended under extensive farming conditions revealed a high seroprevalence (19.3%; 95% CI, 17-22) in the compliment fixation tests. The results of a rapid and simple field test correlated well with the Rose Bengal test (kappa, 0.917) and indicated an acceptable sensitivity (87.5%) and specificity (98.1%) compared with the complement fixation test. Reproductive failure was reported for 39.0% of the cows with a loss of calves due to abortion or early death amounting to 19.3%. Past reproductive failure did not, however, correlate with seropositivity in the complement fixation test (RP = 1.21; P = 0.847). B. abortus biovar 1 was freshly isolated from the hygromas of two cows and together with thirty banked isolates collected since 1990 from different parts of Sulawesi and Timor eight related genotypes could be distinguished with one genotype being identical to that of an isolate (BfR91) from Switzerland. The Indonesian genotypes formed together with BfR91 and one African and one North American isolate a distinct branch on the B. abortus biovar 1 dendogram. CONCLUSIONS: Bovine brucellosis appears to be widespread in the Eastern Indonesian archipelago and calls for urgent intervention. The fresh isolation of the pathogen together with the observed high seroprevalence demonstrates the presence and frequent exposure of cattle in the area to the pathogen. The application of a rapid and simple field test for brucellosis could be very useful for the quick screening of cattle at the pen side.

Comparison of abortion and infection after experimental challenge of pregnant bison and cattle with Brucella abortus strain 2308.

A comparative study was conducted using data from naive bison (n = 45) and cattle (n = 46) from 8 and 6 studies, respectively, in which a standardized Brucella abortus strain 2308 experimental challenge was administered during midgestation. The incidence of abortion, fetal infection, uterine or mammary infection, or infection in maternal tissues after experimental challenge was greater (P < 0.05) in bison than in cattle. In animals that did abort, the time between experimental challenge and abortion was shorter (P < 0.05) for bison than for cattle. Brucella colonization of four target tissues and serologic responses on the standard tube agglutination test at the time of abortion did not differ (P > 0.05) between cattle and bison. The results of our study suggest that naive bison and cattle have similarities and differences after experimental exposure to a virulent B. abortus strain. Although our data suggest that bison may be more susceptible to infection with Brucella, some pathogenic characteristics of brucellosis were similar between bison and cattle.

The role of Brucella infection in abortions among traditional cattle reared in proximity to wildlife on the Kafue flats of Zambia.

The role of Brucella infections in cattle abortions was investigated in 914 females from 124 herds. Animals were tested for exposure to Brucella species and history of abortion over the past three years. Sera were tested using the Rose Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (c-ELISA). Of 886 females tested, 189 were positive on RBT, and 154 (81.5%) were confirmed by c-ELISA. At the individual animal level, 16.2% (95% confidence interval [CI]: 12.6% to 19.8%) of the cows had aborted their foetuses in the last three years, while Brucella seroprevalence was estimated at 23.9% (95% CI: 19.8% to 28.0%), after adjusting for area clustering and weighting according to sampling fraction. At the herd level, abortions were recorded in 50% of the herds (95% CI: 41.2% to 58.8%) and the seroprevalence was 58.1% (95% CI: 49.5% to 66.6%). A multiple logistic regression model identified the presence of anti-Brucella antibodies (odds ratio = 3.4; 95% CI: 1.6 to 7.4) and age as having significant effects on the risk of cattle abortion but no distinct factors could be identified at herd level. These results establish that Brucella infections contribute significantly to cattle abortions in the traditional livestock sector of Zambia.

Seroconversion and abortion in cattle experimentally infected with Brucella sp. isolated from a Pacific harbor seal (Phoca vitulina richardsi).

Previously unrecognized Brucella species have been isolated from a number of marine mammals, including harbor seals (Phoca vitulina richardsi) in the Puget Sound area of the state of Washington. Because of the presence of dairy herds in proximity to the harbor seal populations, a study was conducted to determine the effects of the harbor seal Brucella isolate in experimentally inoculated cattle. Six pregnant cattle were exposed by intravenous injection (n = 3) or intraconjunctival inoculation (n = 3). Two pregnant cows were intravenously injected with saline and served as controls. All of the cows receiving the Brucella seroconverted on 1 or more tests commonly used for the detection of Brucella abortus infection. Two of the cattle receiving the intravenous inoculation aborted, and brucellae were demonstrated in the fetuses and dams immediately following abortion. The remaining 4 Brucella-inoculated animals and their fetuses were culture negative for the organism at 14 weeks postinoculation. Results of this study indicate the marine mammal Brucella is capable of producing seroconversion and abortion in cattle but is less pathogenic in that species than B. abortus.

Brucella melitensis biotype 1 outbreak in goats in northern KwaZulu-Natal.

Brucella melitensis biotype 1 was confirmed in indigenous, outbred goats in three northern districts of the KwaZulu-Natal province following the diagnosis of human Malta fever in the same area. Six foci of infection were found during an extensive serological survey involving 6266 goats carried out in most of the districts of the KwaZulu-Natal province. The prevalence in the positive herds varied between 17% and 100%. The diagnosis was confirmed by culturing milk samples from serologically positive animals. Infected goats were found in only three districts (Ubombo, Ingwavuma and Pongola) and all infected herds fell within a 50-km radius.

Pathogenesis of abortion of bovine brucellosis.

Bovine brucellosis is a major disease of cattle characterized by abortion during the last trimester of gestation. During many years important pieces of research have been done looking for a better understanding of this particular phenomenon. Yet, the fact that the abortion takes place in the last period of gestation result in a fascinating interrogant for such a unique event. The present review includes most of the information available regarding to this matter. Emphasis is done in the interaction of Brucella abortus with the trophoblastic cells of the bovine placenta.

Brucella abortus-associated meningitis in aborted bovine fetuses.

Granulomatous meningitis was present in 6/33 bovine fetuses from which Brucella abortus (B. abortus) had been isolated. Meningitis was severe in three fetuses, moderate in one fetus, and mild in the remaining two fetuses. The meningitis was characterized by the infiltration of a mixed population of lymphocytes, plasma cells, and macrophages in the leptomeninges. Vasculitis characterized by the infiltration of lymphocytes and plasma cells in the vascular wall was observed in the vessels of the cerebral cortices of 4/6 fetuses. Gram negative coccobacilli were present in the cytoplasm of the leptomeningeal macrophages and extracellularly. Brucellar antigens labeled by the avidin-biotin-peroxidase complex method were present in massive amounts in leptomeningeal macrophages and in small foci of stained cells in the choroid plexus and ependyma. The findings indicate that B. abortus is one of pathogens capable of inducing meningitis in bovine fetuses.

Clinical manifestations of brucellosis in cattle of the southern Darfur Province, western Sudan.

Ninety-seven adult Zebu cattle with hygromas, 32 with arthritis and two showing long calving intervals were investigated for brucellosis. 92 per cent of hygromatous cattle, 62 per cent of arthritic cattle and both animals having long calving intervals were serologically positive and 65 per cent of milk samples were positive by the Milk Ring Test. Hygromas were found on the jaw, bursa, thigh, flank, hip, shoulder, neck and joints. Hygroma aspirates gave higher titres than sera in the serum agglutination test. IgG1, IgG2 and IgA were detected in all the aspirates and all but one contained IgM. Cattle with hygromas are a potential source of infection to other animals and a serious public health problem.

Unilateral orchitis in a bull caused by Brucella abortus biotype1.

A case of Brucella orchitis in a Brahman bull is described. Positive serological titres were detected 1 month before clinical symptoms became obvious, whereas the seminal plasma only contained detectable levels of antibody after the onset of orchitis. It is concluded that serological assays on the seminal plasma alone are inadequate to detect sub-clinically infected animals, and consequently particularly bulls that are intended for use in AI centres should be subjected to a full battery of serological tests as well, before they are certified to be free of brucellosis. The pathology seen in this case was an acute, necrotic orchitis characterized by the presence of numerous granulomas containing the Brucella organisms centrally.

Infectious causes of infertility/abortion of cattle in Malawi.

A survey to demonstrate the presence or absence in Malawi of Vibriosis, Brucellosis, Trichomoniasis and Rift Valley Fever was carried out during 1974-1976. 4,876 serum samples were collected from Zebu cattle from 231 dip tanks throughout the country and 145 serum samples were taken from exotic cattle at 14 estates. Sheath washings were collected from 295 bulls representing indigenous Zebus and 54 bulls representing exotic cattle from all parts of Malawi. 245 vaginal mucus samples were taken from exotic breeds and 106 from Malawi Zebus. Vibriosis was found in 34 indigenous bulls and in 6 exotic bulls, 11,5 pct. and 11.1 pct. respectively. 33 vaginal mucus samples from exotic cattle of 13.4 of the samples examined were positive, corresponding to 53.8 pct. of the herds examined. From Malawi Zebus 16 vaginal samples or 15.1 pct. of the samples examined were positive. 5 of the Malawi Zebus tested for Brucellosis using S.A.T. contained a minimum of 100 IU/ml.

[Clinical and epizootiological aspects of bovine, caprine, and ovine brucellosis in Greece]. / Aspects cliniques et épizootiologiques de la brucellose bovine, caprine et ovine, en Grèce

The author reports on an investigation, in Greece, of the clinical and epizootiological aspects of bovine, caprine and ovine brucellosis. These three types of brucellosis are found in the abortive and latent forms. The abortive form is revealed by contagious abortions whose frequency depends principally on the composition of the animal population of the farm; during its evolution, numerous very high positive serological reactions are observed. It involves many complications, causes heavy economic losses and is passed on to a great number of breeders. The latent form is accompanied by chronic manifestations, but passes unnoticed for the most part and is discovered only by serological tests during a period of suspect abortions of human cases of brucellosis. There are fewer of these cases then when the disease evolves in the region in the abortive form. The latent form contributes to the multiplication of centres of infection (1) when apparently uninfected female animals coming from farms contaminated with the latent form are introduced into healthy herds, (2) when the latent form changes into the abortive form after the introduction of healthy female animals into farms contaminated with this form. Furthermore, because of its inapparent evolution, it is a constant danger to rural populations. Bovine brucellosis has been observed in 16 of the 52 departments in the country, and caprine and ovine brucellosis in 21. The proportion of infection throughout the bovine, caprine and ovine herds of the 38 departments in which the investigation was made is approximately 4.70, 1.29, and 0.33 per thousand, respectively. The usual pathogenic agent of bovine brucellosis is Br. abortus; Br. abortus resistant to thionin is found less frequently and Br. melitensis only occasionally. The usual pathogenic agent of caprine and ovine brucellosis is Br. melitensis; Br. intermedia is less frequent and Br. abortus is found only rarely. Four Tables show the clinical investigation of 150 bovine abortions of brucellic origin and observations on the sanitary conditions of 22 cattle-sheds and herds infected with abortive or latent brucellosis. The author concludes in favour of the necessity of medical prophylactic measures and the strict application of sanitary prophylactic measures. In general, new animals should not be introduced into farms but when this is necessary the animal should not be considered free from brucellosis simply because of negative serological reactions. The best policy, in this case, is to repopulate entire farms negative to serological tests by seronegative animals coming also from entirely negative farms.

[Clinical and epidemiological aspects of bovine brucellosis in tropical Africa]. / Aspects cliniques et épidémiologiques de la brucellose bovine en Afrique tropicale

Bovine brucellosis, in the tropical regions of Africa, is very different, both clinically and epidermiologically, from that observed in temperate zones. From the clinical point of view, abortion is rare and extra-genital lesions (hygromas and abscesses) are frequent. From the epidemiological point of view, the rate of infection is low and the disease has very little tendency to spread. The reason for these differences may be explained by climatic conditions (temperature, insolation, humidity) as well as by breeding conditions (principally nomadic or transhumant breeding). Where climatic and breeding conditions resemble those of intensive breeding in temperate zones the clinical and epidemiological aspects tend towards similarity with the usual form of bovine brucellosis.