Seroprevalence and associated risk factors of bovine neosporosis in the Khomas region of Namibia.

Neospora caninum is a coccidian parasite that occurs worldwide and is one of the most important causes of abortion, especially in cattle. However, no studies have been performed in Namibia to determine the N. caninum status in livestock. Therefore, this study aimed to determine the seroprevalence of N. caninum in cattle and the associated risk factors in the Khomas region of Namibia. A total of 736 sera were collected from cows in 32 farming establishments. These comprised 698 beef and 38 dairy cattle sera and were tested using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Questionnaires were concurrently administered to determine possible risk factors associated with N. caninum seropositivity. A total of 42 sera were positive (all beef), giving an animal-level seroprevalence rate of 5.7%. Eight of the 32 establishments had at least one positive animal, giving a herd-level seroprevalence of 25%. There was no significant association between seropositivity and the presence of dogs, jackals, history of abortions, farm size, number of cattle or average annual rainfall. The establishments with moderate to high numbers of Feliformia were 9.8 times more likely to be seropositive to N. caninum than those with none to low levels of the former (p = 0.0245). The authors concluded that the seroprevalence level of N. caninum in the Khomas region was relatively low compared with other parts of the world and that the role of Feliformia in the epidemiology of bovine neosporosis needed to be further investigated.Contribution: Serological evidence of bovine neosporosis and the associated risk factors are reported in Namibia for the first time. This study contributes to the scientific body of knowledge on N. caninum in Africa, which is currently limited.

Evaluation of knowledge, attitudes and practices regarding neosporosis and toxoplasmosis among farmers and animal health practitioners in Namibia.

This study assessed the knowledge, attitudes and practices of livestock farmers in Namibia's Khomas region and animal health practitioners (veterinarians and animal health technicians) in the whole country concerning neosporosis and toxoplasmosis. Structured questionnaires were used, and a total of 63 farmers and 51 animal health practitioners responded out of an estimated 560 farmers in the Khomas region and 300 veterinarians and veterinary technicians in the country. Only 15.9% of the livestock farmers (n = 63) had heard about neosporosis or toxoplasmosis or knew how animals get infected (p < 0.0001). Only 5% of the farmers knew the risks associated with keeping dogs and cats concerning neosporosis and toxoplasmosis, respectively (p < 0.0001). None of the 51 animal health practitioners routinely requested Neospora caninum or Toxoplasma gondii laboratory tests in cases of cattle, sheep or goat abortions. Although all animal health practitioners indicated they routinely interacted with livestock farmers, none regularly discussed neosporosis or toxoplasmosis. Only 3.9% of animal health practitioners (n = 51) indicated that they had ever discussed either neosporosis or toxoplasmosis at a farmers' gathering (p < 0.0001), and only 21.6% had talked to at least one cat owner about toxoplasmosis in the previous 12 months (p < 0.0001). The authors concluded that farmers in the Khomas region were generally unaware of neosporosis and toxoplasmosis but could change their attitudes and practices if educated. The animal health practitioners lacked a deeper understanding and appreciation of the two diseases, which is required to cultivate enough confidence to educate farmers. Sharing this research and other relevant information on the two diseases at farmers' meetings, veterinary congresses, journals and newsletters could help educate farmers and animal health practitioners. Such platforms are likely to succeed because both these groups use these forums to get new information.

International interlaboratory validation of a nested PCR for molecular detection of Babesia bovis and Babesia bigemina, causative agents of bovine babesiosis.

Babesia bovis and B. bigemina are tick-transmitted parasites causing bovine babesiosis, characterized by significant morbidity and mortality leading to economic losses to the livestock industry in tropical and subtropical regions worldwide. Animals that recover from acute infection remain carriers with low parasitemia acting as a source of transmission, and often escape detection. An improved diagnosis of a B. bovis and/or B. bigemina infection of carrier animals is enabled by the availability of detection methods with high sensitivity. To this end, two nested PCR assays targeting the cytochrome b (cytb) genes of B. bovis and B. bigemina (cytb-nPCR), have been recently developed and an increased sensitivity with respect to reference protocols has been shown (Romero-Salas et al., 2016). In this study, the specificity against a panel of hemoparasites that potentially co-occur with B. bovis and B. bigemina was demonstrated to ensure applicability of the cytb-nPCR assays in a wide range of regions where bovine babesiosis is endemic. Furthermore, we compared both reported cytb-nPCR assays with reference nPCR and qPCR protocols for (i) their capability to detect carrier animals in the field, and (ii) their reproducibility when performed in different laboratories by independent operators. We show that, in a panel of bovine field samples (n = 100), the cytb-nPCR assays detected a considerably higher number of 25% B. bovis and 61% B. bigemina-positive animals compared to 7% and 20% B. bovis and 55% and 49% B. bigemina-positive animals when tested by reference nPCR and qPCR protocols, respectively. Cytb-nPCRs were also found superior in the detection of carrier animals when field samples from Africa were analyzed. In addition, both the B. bovis and B. bigemina cytb-nPCR assays were independently validated in a single blinded study in three laboratories. Importantly, no significant differences in the number/percentage of infected animals was observed using cytb-nPCR assays. In summary, the cytb-nPCR assays detected a considerably higher number of chronically infected B. bovis and B. bigemina carrier animals compared to reference nPCR and qPCR protocols, when applied in different epidemiological field situations. Furthermore, a high reproducibility between laboratories could be demonstrated.

Autochthonous canine babesiosis in The Netherlands.

Outbreaks of autochthonous babesiosis, caused by Babesia canis, occurred in The Netherlands in the spring and autumn of 2004 affecting 23 dogs. Nineteen animals recovered after treatment, whereas four dogs died. Adult Dermacentor reticulatus ticks collected from these dogs indicate that canine babesiosis could become endemic in The Netherlands.