Investigation of the outbreaks of abortions and orchitis in livestock in Namibia during 2016-2018.

This study investigated outbreaks of seemingly related abortions and orchitis which occurred in the Khomas, Omaheke and Otjozondjupa regions of Namibia from 2016 to 2018, affecting cattle, sheep and goats. Fifty-nine questionnaires were administered, and 48 were completed giving an 81.4% return. The outbreaks were limited to Namibia's east and central regions, mainly on farms rearing cattle, sheep and goats and on farms with a mixture of these species. There was no significant difference between Khomas and other regions on abortion reporting at the farm level [X2 (1, N = 48) = 0.0002, p = 0.987851]. However, there was a significant difference in the abortions at the animal level among the three regions [X2 (2, N = 6246) = 239.8339, p = .00001]. In addition, the proportions of abortions calculated at the animal level at each farm were significantly different when the Khomas region was compared to the other regions. Seventeen cattle sera, 35 sheep sera, 52 caprine sera, 18 bovine liver samples, one caprine liver, five aborted cattle foetuses, two cattle placentas, 18 testes (one bull, eight bucks and nine rams) and ten bull sheath scrapings were collected and tested. Histopathology, microbiology, serology, immunohistochemistry, real-time PCR and mineral analytical techniques were used to establish the aetiology of the abortion and orchitis outbreaks. The gross and histopathological findings on the 18 testicles were characteristic of chronic orchitis. In aborted foetuses, significant histopathological findings included meconium aspiration, funisitis and cardiomyopathy. Placentitis and endometritis were the primary pathologies observed in cows. The bacteria isolated from microbiological samples included Enterococcus spp. (65.5% [19/29]), Enterobacter spp. (6.9% [2/29]) and Streptococcus spp. (10.3% [3/29]), Trueperella pyogenes (3.4% [1/29]), Stenotrophomonas maltophilia (3.4% [1/29]), Staphylococcus epidermidis (3.4% [1/29]), Providencia rettgeri (3.4% [1/29]) and Acinetobacter lwoffii (3.4% [1/29]), mostly opportunistic bacteria. On mineral analysis, 28%, 33%, 83%, 33% and 17% (n = 18) of cattle livers were low in copper, zinc, manganese, selenium and iron, respectively. Twenty-three percent (12/52) of the caprine sera were positive for Brucella melitensis on the Rose Bengal and complement fixation tests. Thirty-five ovine sera were tested for B. melitensis, B. ovis and Coxiella burnetii, and the prevalence for each was 2.9% (1/35). PCR tests on foetuses were all negative for Brucella spp., Coxiella burnetii, Chlamydia spp., Listeria monocytogenes, Salmonella spp., Campylobacter fetus spp., Leptospira pathogenic strains, bovine viral diarrhoea virus, Rift Valley fever virus, Anaplasma phagocytophilum and bovine herpes virus 4 Campylobacter fetus spp. and Trichomonas foetus spp. The authors concluded that Brucella spp., Enterococcus spp., Escherichia coli, Streptococcus spp., Trueperella pyogenes and Coxiella burnetii could have contributed to this outbreak. Micronutrient imbalances and pathogenic abiotic nanoparticles were also identified as possible contributors to the abortion outbreaks.

Production performance of sheep and goat breeds at a farm in a semi-arid region of Namibia.

This study retrospectively investigated the effect of breed and season on the lambing/kidding dynamics, growth performance, neonatal viability, and weaning dynamics of sheep (Damara, Dorper, and Swakara) and goats (Boer goat and Kalahari Red) at a farm in the Khomas Region of Namibia between 2004 and 2015. Litter size was dependent on breed (X2(12, N = 3388) = 796, p < 0.001), with twinning more frequent in Dorper sheep and Kalahari Red and Boer goats than in the Damara and Swakara sheep (p < 0.05), while triplets were more prevalent in the Dorper sheep and Kalahari Red goats (2.8% and 1.0%, respectively; p < 0.05). Distribution of birth weight categories was dependent on breed. There was a significant difference in the proportions of birth weight categories between breeds (X2(12, N = 3388) = 467, p < 0.001) whereby Dorper lambs were mostly born weighing below 3 kg (2.6%, p < 0.05); Boer goat kids, Kalahari Red kids, and Damara lambs were mostly born weighing 3 to < 4 kg (4.3%, 6.3% and 19.9%, respectively; p < 0.05); Swakara lambs were mostly born weighing 4 to < 5 kg (12.2%, p < 0.05), and Swakara lambs were mostly born weighing ≥ 5 kg (3.3% and 2.3%, respectively, p < 0.05). Weaning age categories were dependent on breed (X2(12, N = 3388) = 241, p < 0.001) whereby Dorper lambs were mostly weaned at below 3 months of age (2.8%, p < 0.05); Damara lambs were mostly weaned at 3 to < 5 months of age (12%, p < 0.05), and Boer goat kids were mostly weaned at ≥ 5 months of age (0.9%, p < 0.05). Neonatal viability was dependent on breed (X2(8, N = 3388) = 49.2, p < 0.001) whereby Dorper lambs were more susceptible to abortions and neonatal deaths (0.6% and 1.5%, respectively; p < 0.05) than the rest of the breeds. Breed and lambing season interacted to produce effects on the birth weight of offspring although lambing season alone did not have a significant effect on Boer goat and Kalahari Red kids' birth weights.

A feather cyst causing vertebral bone lysis and spinal cord compression in a Lohmann Brown layer.

A feather cyst in the cervical region which, through complications of inward growth, resulted in compression of the cervical spinal cord of a Lohmann Brown layer is described. It is postulated that expansion of the cyst exerted pressure on the adjacent cervical vertebra and through bone lysis created an opening through which the cyst protruded, thereby exerting pressure on the spinal cord. The affected spinal cord segment was reduced to a fifth of its normal diameter. The bird most likely died of starvation because of limb and neck paralysis and disorientation. Although the cause of the feather cyst was not conclusively identified, moulting and trauma could have triggered its formation and subsequent growth.

African Swine Fever Outbreak at a Farm in Central Namibia.

An outbreak of African swine fever (ASF) occurred at a farm in central Namibia in March 2018. Fourteen pigs died out of a herd of 59 animals over a period of 16 days between the first and sixteenth of March 2018. The clinical signs observed included sternal recumbency, fever, weakness, pain and reluctance to move, hyperemia of the skin and anorexia, followed by death. Necropsy findings included large amounts of unclotted blood in the pleural and peritoneal cavities, diffuse carcass congestion, splenomegaly, consolidation of both lungs, hemorrhagic and frothy airways and trachea, hepatomegaly and congestion, congestion of the gastric mucosa, enlarged and congested kidneys, ecchymotic epicardial, and endocardial hemorrhages, and very enlarged and congested urinary bladder. All the remaining pigs were euthanized, burned, and buried under state veterinary supervision. The authors concluded that the outbreak resulted from indirect transmission of the ASF virus due to lapses in biosecurity measures.

Characterization of Oestrus Cycles in Namibian Swakara and Damara Sheep through Determination of Circannual Plasma Progesterone Levels.

A year-long prospective study characterized the seasonality of oestrus cycles in primiparous, nonpregnant Swakara (n=8) and Damara (n=5) ewes through surveillance of plasma progesterone (P4) levels. During this period, Swakara and Damara groups evidently averaged 23 oestrus cycles with an average length of 17 days. Damara ewes showed greater mean peak plasma P4 levels (11.4±0.16ng/ml) than Swakara ewes (5.4±0.11ng/ml) (P<0.05). Oestrus cycles in Damara ewes showed relatively uniform plasma P4 peaks throughout the year ranging from 10.6±0.16 to 12.6±0.24ng/ml. In Swakara ewes, P4 peaks were highest in the autumn oestrus cycles (from 7.1±0.16 to 7.5±0.11ng/ml), rapidly declining through winter to 2.2±0.08ng/ml by midspring and then rapidly increasing to 4.9±0.37ng/ml at the commencement of summer, followed by a gradual increase from 5.7± to 7.1±ng/ml by the start of autumn. The annual mean area under the curve temporal progesterone measurements (AUCPM) in Damara ewes (115.9±18.6ng⁎day/ml) was greater than that in Swakara ewes (58.6±25.3ng⁎day/ml) (p<0.05). For Swakara ewes, the mean AUCPM in summer and autumn cycles (68.2±14.7 and 79.5±10.0ng⁎day/ml, respectively) were greater than those in spring and winter cycles (28.7±12.3 and 55.0±27.3ng⁎day/ml), respectively (P<0.05). There was no seasonal variation in the exposure of the Damara ewes to P4 in between seasons (P>0.05), though, however, the Damara ewes had greater P4 levels than the Swakara ewes (P<0.05). Progesterone profiles showed that Swakara ewes possessed 'residual' seasonality, whereas the Damara ewes were no longer seasonal. The implications of this disparity in the seasonal exposure of Swakara and Damara ewes to luteal P4 on fertility warrant further investigation.

Ecology and epidemiology of rabies in humans, domestic animals and wildlife in Namibia, 2011-2017.

Rabies is a fatal zoonotic disease that causes a heavy burden on societies. Namibia, a country in southern Africa, is aiming at controlling the disease in its main reservoir, the domestic dog. To facilitate the implementation comprehensive information on the ecology and epidemiology of the disease and surveillance is of utmost importance. The study presented assesses the baseline data for both human and animal rabies surveillance in Namibia in recent times and establishes correlations with ecological and socio-economic data in order to provide an up-to-date picture on the epidemiology of rabies in Namibia. For instance, it was important to identify the main drivers in the epidemiology, and whether the control strategy by mass vaccination of dogs is undermined by cycles of rabies in wildlife. Rabies in humans was reported mainly from the Northern Communal Areas (NCAs), with a total of 113 cases from 2011 to 2017, representing an incidence of between 1.0 and 2.4 annual human rabies deaths per 100,000 inhabitants. Kavango, the region with the highest human rabies incidence was also the region with the lowest animal rabies surveillance intensity. Generally, the vast majority (77%) of dog samples originated from communal farm land, followed by urban areas (17%), while only a small fraction (3%) was submitted from freehold farm areas. In contrast, kudu and eland submissions were almost exclusively from freehold farmland (76%) and urban areas (19%), whereas the submission of cattle samples was evenly distributed among freehold farms (46%) and communal farm land (46%). The likelihood of sample submission decreased exponentially with distance to one of the two laboratories. Overall, 67% (N = 1,907) of all samples submitted tested rabies-positive, with the highest positivity rate observed in kudus (89%) and jackals (87%). The transmission cycle of rabies in dogs appears restricted to the northern communal areas of Namibia, whilst rabies in wildlife species is predominately reported from farmland in central Namibia, mostly affecting kudu (Tragelaphus strepsiceros) and livestock with a likely reservoir in wildlife canids such as jackals or bat-eared foxes. The analysis confirms the presence of two independent transmission cycles in Namibia with little geographic overlap, thus allowing for a sustainable control of rabies in dogs in the NCAs.

Conception rates and calving intervals of different beef breeds at a farm in the semi-arid region of Namibia.

A retrospective study from 2004 to 2017 investigated the effect of bull age, cow age and breed on conception rates, and calving intervals of beef cattle at Neudamm farm, Khomas region, Namibia. Bulls ranging from 4 to 14 years of age were used to breed cows up to 17 years of age. A total of 1804 pregnancies were diagnosed in Afrikaner (81.8%), Nguni (14.1%), and Simmental (4.1%) cows. The overall conception rate of beef cattle during the study period was 71.7 ± 9.5%. The overall conception rate of the Nguni cows (78.3%) was significantly higher than that of the Afrikaner (70.9%) and the Simmental cows (64.9%) (p < 0.05). The age of sires had no effect on overall conception rate in all three breeds (p > 0.05). Afrikaner dams more than 10 years old had the least rate of conception (60.4%, p < 0.05) within that breed category. Nguni dams between four to 10 years had the greatest conception rate (86.5%, p < 0.05). Age of dams had no effect on conception rates in Simmental cattle (p > 0.05). The overall mean length of all calving intervals in the Nguni cows (366 ± 35 days) was significantly shorter than those of the Afrikaner cows (487 ± 62 days) and the Simmental cows (484 ± 110 days) (p < 0.05). The 2013 breeding season produced the highest overall conception rates (~ 85%), and the 2007 breeding season produced the lowest overall conception rate (~ 51%). From a fertility point of view, the Nguni breed seemed best suited for the semi-arid conditions which are prevalent in most of Namibia.

Study of Incidence of Gross Urogenital Lesions and Abnormalities on Does Slaughtered at Nyagatare Slaughterhouse, Eastern Province, Rwanda.

Reproductive and urinary tract abnormalities are a cause of infertility, reproductive inefficiency, and economic losses in goats. The aim of this study was to investigate the occurrence and nature of reproductive and urinary tract abnormalities encountered in female goats slaughtered at Nyagatare abattoir in the Eastern Province of Rwanda. Reproductive and urinary organs from 369 female goat carcasses were opened by incision and then given a thorough macroscopic examination by visually inspecting and palpating for evidence of abnormalities. The results showed that there was an overall occurrence of 7.8% reproductive organ/tract abnormalities and 10.6% urinary organ/tract abnormalities. Ovarian hypoplasia was the reproductive abnormality with the highest overall occurrence (32.3%) and renal calculi were the urinary organ abnormality with the highest occurrence (38.1%). 95.2% of the reproductive organ/tract abnormalities observed usually result in infertility and 91.3% of the urinary organ/tract abnormalities observed result in economic losses through condemnation of kidneys at slaughter. The high incidence of the observed urinary organ/tract abnormalities represents a potential public health challenge. There was no significant difference in the occurrence of reproductive organ/tract abnormalities according to breed (p > 0.05, n = 31). There was also no significant difference in the occurrence of urinary organ abnormalities according to breed (p > 0.05, n = 42).

Rift Valley fever in Namibia, 2010.

During May-July 2010 in Namibia, outbreaks of Rift Valley fever were reported to the National Veterinary Service. Analysis of animal specimens confirmed virus circulation on 7 farms. Molecular characterization showed that all outbreaks were caused by a strain of Rift Valley fever virus closely related to virus strains responsible for outbreaks in South Africa during 2009-2010.