Positivity and Intensity of Gnathostoma spinigerum Infective Larvae in Farmed and Wild-Caught Swamp Eels in Thailand

From July 2008 to June 2009, livers of the swamp eels (Monopterus alba) were investigated for advanced third-stage larvae (AL3) of Gnathostoma spinigerum. Results revealed that 10.2% (106/1,037) and 20.4% (78/383) of farmed eels from Aranyaprathet District, Sa Kaeo Province and those of wild-caught eels obtained from a market in Min Buri District of Bangkok, Thailand were infected, respectively. The prevalence was high during the rainy and winter seasons. The infection rate abruptly decreased in the beginning of summer. The highest infection rate (13.7%) was observed in September and absence of infection (0%) in March-April in the farmed eels. Whereas, in the wild-caught eels, the highest rate (30.7%) was observed in November, and the rate decreased to the lowest at 6.3% in March. The average no. (mean±SE) of AL3 per investigated liver in farmed eels (1.1±0.2) was significantly lower (P=0.040) than those in the caught eels (0.2±0.03). In addition, the intensity of AL3 recovered from each infected liver varied from 1 to 18 (2.3±0.3) in the farmed eels and from 1 to 47 (6.3±1.2) in the caught eels, respectively. The AL3 intensity showed significant difference (P=0.011) between these 2 different sources of eels. This is the first observation that farmed eels showed positive findings of G. spinigerum infective larvae. This may affect the standard farming of the culture farm and also present a risk of consuming undercooked eels from the wild-caught and farmed eels

Immunodiagnosis of human trichinellosis using excretory-secretory (ES) antigen

ABSTRACTInfective first stage larvae ofTrichinella spiraliswere recovered from muscles of laboratory infected mice by digesting the muscles with 1% HC1–1% pepsin and collecting the larvae by modified Baerman's method. The larvae were cultivated in a serum-free medium for 18 h. The ES antigen obtained from the culture medium was used in an enzyme-linked immunosorbent assay (ELISA) for detecting IgG antibodies toT. spiralisin serum samples collected from three groups of individuals. The individuals of the first group were parasitologically confirmed trichinellosis patients, while those of group 2 were patients with other helminthiasis and group 3 were healthy, parasite-free individuals. The specificity of the assay was 100%. The sensitivity of the test was also 100% when performed on sera of group I collected at days 57 and 120 after infection. Sera collected earlier (day 23) and those collected 700 days after infection had negligible reactivity. Thus IgG-ELISA using ES antigen of the L1was useful not only for diagnosis but also in evaluation of cure. Western blot analysis revealed that specific antigens ofT. spiraliswere 94, 67, 63, and 39 kilodalton components.</jats:p