Background: Porcine cysticercosis is an emerging agricultural problem in sub-Saharan Africa. This has been
documented primarily through cross-sectional studies, however detailed knowledge of the transmission dynamics
of this disease in sub-Saharan Africa is lacking. This study aims to describe seasonal variations in sero-prevalence of
antigen ELISA positive porcine cysticercosis in an endemic area.
Methods: A longitudinal study composed of three cross-sectional surveys was carried out in Mbeya Region,
Tanzania; the first two six months apart (March/April 2012 and October/November 2012) and the last eight months
later (July/August 2013). Venous blood was collected from pigs in 22 villages and analysed using Ag-ELISA.
Results: In each survey between 800–1000 serum samples were collected. The first survey revealed a cysticercosis
sero-prevalence of 15% (n = 822, 95% CI: 13-18%). The sero-prevalence had significantly increased to 24% (p < 0.001,
χ2-test, n = 812, 95% CI: 21-27%) at the time of the 6 month follow-up. At 14-months the sero-prevalence had
dropped to 20% (p = 0.053, χ2-test, n = 998, 95% CI: 18-23%). Overall, this was a reduction in sero-prevalence
compared with a study conducted in 2007 in the same area, where 31% (186/600) of pigs were found positive.
Conclusion: Confined pigs did not have a lower sero-prevalence compared to free roaming pigs in any of the three
surveys. Several factors may have contributed to the observed fluctuations such as African swine fever or seasonal
variation in local crop production practices. Also, as the Ag-ELISA assay used is not species specific, variation in
transmission of Taenia hydatigena could potentially influence the results. The observed fluctuations contradict a theoretical
model which predicts a stable equilibrium, which only considers a two-compartment (pig and human) model excluding
the effect of the environment. Whether the disease has an endemic equilibrium, or undergoes fluctuations dependent on
extrinsic and/or socio-economic factors remains to be elucidated.