Antibodies against Rift Valley Fever Virus in Cattle, Mozambique

Rift Valley Fever Outbreak in Livestock, Mozambique, 2014

“…Seroprevalences of 9.2% in sheep and 11.6% in goats was recorded in Zambézia Province (7). In Maputo Province, an overall seroprevalence of 36.9% was documented in cattle (8). The results indicated the possible circulation of RVF virus during interepidemic periods without the manifestation of typical clinical signs, as has been described elsewhere (9).…”

Rift Valley Fever Outbreak in Livestock, Mozambique, 2014

“…), the conditions for an increase in the vector population, and therefore in virus circulation, favored the occurrence of the outbreaks. The high level of seroprevalence reported previously in districts close to the study site ( 8 ) may suggest a continuous low level of virus transmission in the region that is exacerbated by above-average rainfall, resulting in RVF virus infection in naive animals. …”

Drivers for Rift Valley fever emergence in Mayotte: A Bayesian modelling approach

“…In addition, since our livestock population did not experience the classical symptoms of RVF (waves of abortions and high mortality in newborn), disease-induced mortality was not explicitly modelled. Sub-clinical forms were common for RVF in Mayotte, as well as in the neighbouring Union of Comoros and Mozambique [ 23 , 41 – 43 ]. Also, sheep, the most susceptible species to clinical symptoms, only represents 3–4% of the livestock population of the island.…”

“…The rate at which animals are ageing at each time-step is noted δ; α is the survival rate for the age-groups 1–9, and α 10 for the age-group 10; and finally b t is the birth rate. No disease-related mortality was accounted for because such symptoms were not reported at that time in Mayotte, neither in the neighbouring Comoros and Mozambique RVF affected areas [ 23 , 41 – 43 ]. In addition, since the animal population was not fully susceptible at the beginning of our study period (October 2004), a proportion of immune animals ( imm_t 0 ) was specified at t 0 , such as: …”