Evaluation of crude adult Ascaris suum intestinal tract homogenate in inducing protective IgG production against A. suum larvae in BALB/c mice.

Globally, ascariasis ranks as the second leading intestinal helminth infection. However, progress in developing better control strategies, such as vaccines, remains slow-paced. This study aims to measure antibody production and parasite load in male BALB/c mice immunized with crude Ascaris suum intestinal tract homogenate. Thirty-two (32) mice were randomized into: (1) unvaccinated, uninfected (UU); (2) unvaccinated, infected (UI); (3) vaccinated, uninfected (VU); and (4) vaccinated, infected (VI) groups. A 100-µL vaccine containing 50 µg of homogenized A. suum intestines and Complete Freund's Adjuvant (1:1) were introduced intraperitoneally. Immunizations were done on days 0, 10, and 20. Oral gavage with 1000 embryonated eggs was done on day 30. Blood was obtained at day 40. To measure serum IgG levels, indirect ELISA was done. Microtiter plates were coated with 100 µg larval homogenate, and HRP-conjugated anti-mouse IgG was used as secondary antibody. Parasite load was measured in lung and liver tissues. Tukey's HSD of signal to cut-off ratios of absorbance readings obtained in indirect ELISA procedure for the 1:200 serum dilution showed statistically significant difference between the UU and VI (p = 0.026) as well as between UI and VI (p = 0.003) groups. No statistically significant difference in parasite load was observed in the lungs (p = 0.074), liver (p = 0.130), and both lungs and liver (p = 0.101). Immunization elicited a significant larva-directed IgG production. However, there is no significant difference in parasite loads in either lung or liver tissues across all treatment groups as the larval counts obtained from the study were very low and may not be indicative of the actual parasite load in mice.

Correlation between blood ethylenethiourea and thyroid gland disorders among banana plantation workers in the Philippines.

Ethylenebisdithiocarbamates (EBDCs) are metabolized into ethylenethiourea (ETU), a possible human carcinogen and an antithyroid compound. In this study our goal was to correlate ETU levels with the incidence of thyroid gland disorders among banana plantation workers exposed to EBDC. We randomly selected 57 directly exposed workers and 31 indirectly exposed workers from four banana plantations and 43 workers from an organic farm; all subjects underwent complete medical examinations and laboratory tests. Results showed a higher mean thyroid-stimulating hormone measurement among exposed workers compared with the control group, although the levels were well within normal range. Nine of the exposed farmers had abnormal thyroid ultrasound findings, consisting mostly of solitary nodules, compared with three among the control group. Analysis of variance showed significantly different blood ETU levels among the directly exposed, indirectly exposed, and control groups (p < 0.001), but ETU levels in urine were not significantly different (p = 0.10). Environmental ETU levels were below the U.S. Environmental Protection Agency remediation levels. Among farmers with solitary thyroid nodules, we found a very good direct correlation between the size of the nodule and blood ETU level. In this study we showed that blood ETU is a more reliable biomarker for EBDC exposure than urinary ETU; therefore, the determination of blood ETU should be part of medical surveillance efforts among workers exposed to EBDC to detect occurrences of thyroid gland disorders.