Assessment of routine inspection methods for porcine cysticercosis in Zambian village pigs

Abstract

The value of tongue and meat inspection as diagnostic tools for porcine cysticercosis was assessed in 65 Zambian village pigs by comparing the results with carcass dissections. In addition, the intensity of infections, distribution and viability of cysts in infected pigs were measured. Five pigs (7.7%) were positive on tongue examination, while routine meat inspection showed 12 (18.5%) positives. However, carcass dissections detected cysticerci in 31 (47.7%) pigs. The range in number of cysticerci was 1 to 14,662 per carcass. Cysticerci were distributed throughout the carcass with the highest concentration in the heart, tongue and hind legs. In one animal 13 viable cysts were detected only in the brain. Fourteen pigs had more than 100 viable cysts, six between 2 and 100, and four had single cyst infections. Seven animals harboured only calcified cysts. These findings demonstrate the serious shortcomings of routine detection methods for porcine cysticercosis. While the specificity of tongue palpation and meat inspection was 100%, these tests failed to detect the infection in 83.9% and 61.3% of infected pigs, respectively.

Cysticercosis in experimentally and naturally infected pigs: parasitological and immunological diagnosis

“…Detailed necropsy was then performed only on the experimentally infected pigs, from which the entire musculature and organs were cut into thin slices of about 0.5cm (Boa et al 2002). The cysticerci were classiϐied as vesicular and non-vesicular based on their macroscopic appearance (Phiri et al 2006).…”

“…Dorny et al (2004) describe a similar ϐinding and estimated the sensitivity of tongue examination and carcass inspection to be 21 and 22%, respectively. Phiri et al (2006) also found that pigs with a low parasite burden did not test positive through tongue examination and carcass inspection, as these methods failed to detect cysticercosis in 83% and 61% of the animals, respectively. In endemic areas, most commercialized pigs with light infection may escape from being detected by meat inspection and the consumption of undercooked pork meat is therefore a risk factor for infection.…”

“…While the technique is very speciϐic (100%), it is not very sensitive when used on pigs with a low cyst burden (Sciutto et al 1998, Boa et al 2002, Phiri et al 2006, Soares et al 2006). …”

Serological responses in porcine cysticercosis: A link with the parasitological outcome of infection

“…Viable cysticerci had well-limited thin-walled cystic structures containing clear vesicular fluid and a visible whitish protoscolex. Degenerated cysticerci were non-cystic but rather had semi-solid caseous masses with no discernible parasite structures (Phiri et al, 2006). This experiment was reviewed and approved by the Committee on Animal research of the School of Veterinary Medicine, UNMSM.…”

Complexities in using sentinel pigs to study Taenia solium transmission dynamics under field conditions

“…The thickness of the slices was <0.5 cm, ensuring exposure of fully developed cysts (Phiri et al, 2006). Cysticerci and cysticercus-like structures were sought in muscles and organs, and after removal stored in ethanol 70% for molecular identification of the Taenia species.…”