Recent studies in the Democratic Republic of Congo suggest that pork trade may affect the transmission of the parasite Taenia solium, also known as the pork tapeworm, selecting highly infected pigs at village level.
The study, by scientists from various research institutes in Belgium and Congo, which was published last month, dived into the topic of the parasite's prevalence.
T.solium is a zoonotic parasite that is endemic in most developing countries where pork is consumed, is recognised as the main cause of acquired epilepsy in these regions. The parasite has been reported in almost all of the neighboring countries of Democratic Republic of Congo (DRC) but data on the current prevalence of the disease in the country itself are lacking.
T.solium is a parasite that can affect both humans and pigs, causing important economic losses in pig production and being the main cause of acquired epilepsy in endemic areas.
This study, focusing on porcine cysticercosis (CC), makes part of a first initiative to assess whether cysticercosis is indeed actually present in DRC.
An epidemiological study on porcine CC was conducted on urban markets of Kinshasa where pork is sold and in villages in Bas-Congo province where pigs are traditionally reared. Tongue inspection and ELISA for the detection of circulating antigen of the larval stage of T.solium were used to assess the prevalence of active CC in both study sites.
The overall prevalence of pigs with active cysticercosis did not significantly differ between the market and the village study sites (38.8 [CI95%: 34–43] versus 41.2% [CI95%: 33–49], respectively). However, tongue cysticercosis was only found in the village study site together with a significantly higher intensity of infection (detected by ELISA).
The studies demonstrated high prevalence figures of active infections in villages in a rural area of DRC and in markets in the city of Kinshasa. The intensity of infection, however, was higher in pigs sampled in villages as compared to pigs sampled on urban markets.
The researchers offered the following explanation for this phenomenon: “Pigs reared at village level are sold for consumption on Kinshasa markets, but it seems that highly infected animals are excluded at a certain level in the pig trade chain. Indeed, preliminary informal surveys on common practices conducted in parallel revealed that pig farmers and/or buyers select the low infected animals and exclude those who are positive by tongue inspection at village level.”