Controlled tests of pastes of dichlorvos and thiabendazole against induced Strongyloides westeri infections in pony foals in 1973-1974.

The research explores the effectiveness of dichlorvos and thiabendazole pastes in treating pony foals infected with the Strongyloides westeri parasite. The investigation revealed that dichlorvos, particularly at a dosage rate of 44 mg/kg, was highly successful in eliminating intestinal infections of S. westeri.

Research Methodology

• The study took place in 1973-1974 and included four separate tests. All the tests involved pony foals, with a total of 17 ponies involved.
• The pony foals were initially raised in a parasite-free environment and afterwards, these foals were experimentally infected with the Strongyloides westeri parasite.
• The delivery of infective larvae was done through different methods, including stomach tube, intraoral administration and percutaneous (intra-aural) administration.
• The researchers noted that the use of a stomach tube for larvae administration tended to result in low-grade infections, and so it possibly invalidated the results of the test in question. Higher grade infections, which were seen as more suitable for the tests, were achieved through intraoral and percutaneous (intra-aural) methods.

Testing of Dichlorvos

• One of the substances tested was a paste formulation of dichlorvos. This was administered at a dosage rate of 36.3 mg/kg of the body weight of the foals.
• The result of dichlorvos treatment was observed by calculating the parasite removal rate. For instance, complete removal of parasites was observed in four of the ponies that received the treatment.

Dichlorvos Effectiveness

• The research found that a higher dosage level of dichlorvos, at 44 mg/kg of body weight, was highly effective at getting rid of the intestinal infections in the pony foals.
• The paste displayed a consistent effectiveness rate of 99-100% at this dosage rate.

In conclusion, the study demonstrated that dichlorvos can effectively treat parasite-induced infections in pony foals, particularly when administered at a dosage rate of 44 mg/kg of body weight.