Seroprevalence of bluetongue virus in dairy herds with reproductive problems in Sudan.

The objectives of this cross-sectional study were to determine the seroprevalence of blue tongue virus (BTV) and assess potential risk factors associated with BTV infection in dairy cattle with reproductive problems in Sudan. Serum samples were collected from a total of 784 animals from 37 herds and tested for antibodies against BTV using cELISA. A total of 663 out of 784 (84.57%) sera tested proved positive for BTV antibodies in all farms tested in Khartoum and Gazira States. The prevalence of antibodies was high in both areas being 94.32% in Gazira State and 76.62% in Khartoum State. BTV antibodies prevalence were significantly higher (P < 0.000) in older animals than in younger ones. These rates were also significantly higher in the rainy season (P < 0.000) and in Gazira State compared to Khartoum State. Sex also showed significant (P < 0.000) differences in the seroprevalence, whereby females (74.7%) had higher level than males (9.8%). However, no significant (P > 0.09) variations for BTV seroprevalence were observed between breeds. The BTV antibodies prevalence in infertility cases (86.6%) was not significantly different from that found in abortion (74.3%) or neonatal death (66.7%) cases. The high seroprevalence of BTV recorded herein calls for control strategy to be implemented.

First report of Neospora caninum infection in cattle in Sudan.

A cross-sectional survey was conducted in Sudan to determine sero-prevalence and risk factors associated with Neospora caninum infection in non-vaccinated dairy herds and to assess importance of the disease. Blood samples were collected from a total of 262 animals from 25 herds. Sera were tested for antibodies against N. caninum using ELISA test. The prevalence rates of N. caninum antibodies in cattle were high both at herd level (44%) and at individual animal level (10.7%). Herd level infection rates were similar in Khartoum State (43.7%) and at Gazira States (44.4%). The overall prevalence rates were higher (16.1%) in Gazira State than in Khartoum State (9%) but with no significant variation. The sero-prevalence at individual animal level was significantly higher (p < 0.05) in animals with history of abortion (12.8%) than in apparently healthy animal (11.3%), animal with history of infertility (8.1%), or neonatal death of calves (4.3%). In addition, significantly higher (P < 0.05) sero-prevalence was observed in samples collected during the rainy season (6.87%) than winter (3.05%) or summer (0.76%). However, no significant differences in sero-prevalence due to locality, animal breed, sex, and age were observed (p > 0.05). This preliminary study reveals for the first time the existence of natural N. caninum infection in Sudan. Also, the findings of the present study indicated that this disease is highly prevalent in two major areas of dairy production in the country, and this calls for control strategy to be implemented.

Spotted fever group rickettsiae from ticks captured in Sudan.

Ticks were collected from ruminants in various areas of Sudan in 1998 and 2000. Primer pairs of rickettsial citrate synthase gene (gltA) and a spotted fever group (SFG) rickettsial 190-kDa surface antigen gene (rompA), respectively, were used for identification. Polymerase chain reaction (PCR)-positive products were used for DNA sequencing. The gltA gene was detected in 55% of the ticks examined (57/104). Among the 57 ticks studied, 19 were positive for the rompA gene. Thus, 18% of the ticks examined were found to be infected with SFG rickettsiae. The nucleotide sequences of the amplified rompA gene fragment of Hyalomma spp. and Amblyomma spp. were similar to those of Rickettsia aeschlimannii and Rickettsia africae, respectively. In this study, we succeeded in detecting the SFG rickettsiae gene in ticks, and established that there were at least two species of SFG rickettsiae in field ticks in Sudan.