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Biomedical subjects

S K Ault

Publications and source records attributed to S K Ault.

5 recordsLinked to original sources

Environmental management: a re-emerging vector control strategy.

Vector control may be accomplished by environmental management (EM), which consists of permanent or long-term modification of the environment, temporary or seasonal manipulation of the environment, and modifying or changing our life styles and practices to reduce human contact with infective vectors. The primary focus of this paper is EM in the control of human malaria, filariasis, arboviruses, Chagas' disease, and schistosomiasis. Modern EM developed as a discipline based primarily in ecologic principles and lessons learned from the adverse environmental impacts of rural development projects. Strategies such as the suppression of vector populations through the provision of safe water supplies, proper sanitation, solid waste management facilities, sewerage and excreta disposal systems, water manipulation in dams and irrigation systems, vector diversion by zooprophylaxis, and vector exclusion by improved housing, are discussed with appropriate examples. Vectors of malaria, filariasis, Chagas' disease, and schistosomiasis have been controlled by drainage or filling aquatic breeding sites, improved housing and sanitation, the use of expanded polystyrene beads, zooprophylaxis, or the provision of household water supplies. Community participation has been effective in the suppression of dengue vectors in Mexico and the Dominican Republic. Alone or combined with other vector control methods, EM has been proven to be a successful approach to vector control in a number of places. The future of EM in vector control looks promising.

Animals

Exotic stock of Trypanosoma cruzi (Schizotrypanum) capable of development in and transmission by Triatoma protracta protracta from California: public health implications.

A stock of Trypanosoma cruzi was recovered from a Triatoma dimidiata from Tegucigalpa, Honduras. This stock was shown to be capable of development and transmission by native California Triatoma protracta protracta. Isozyme analysis indicated that this T. cruzi is closely related to the Tehuantepec strain and to a lesser extent the Miles' zymodeme 1 strain. The potential public health significance of development and transmission of exotic stocks of T. cruzi by native reduviids is discussed.

Animals

Agent of Chagas' disease from Honduran vector capable of developing in California insects: implications for cardiologists.

An exotic strain of Trypanosoma cruzi recovered from Triatoma dimidiata from Tegucigalpa, Honduras, was shown by isoenzyme studies to be closely related to the Miles' zymodeme 1 and laboratory reference strain Tehuantepec. It was injected into Swiss random-bred ICR mice. Clean Triatoma protracta nymphs and adults, which had been captured in Winters, California, fed on inoculated mice and were then examined over a 15-month period. Their feces contained multiplying epimastigote and infective trypomastigote forms of T. cruzi. This shows that exotic strains of T. cruzi can develop and survive for long periods in local California vectors. The increasing number of immigrants from Central America who enter California and other states may have public health implications in regard to the introduction of pathogenic strains that are capable of producing cardiomyopathy. Cardiologists who examine patients with cardiomyopathy from Central and South America should rule out Chagas' disease as a cause, since pathogenic T. cruzi strains are present in most Central and South American countries.

Animals

Viral agents recovered from Ornithodoros coriaceus, a vector of epizootic bovine abortion.

Two unidentified viral isolates from the tick, Ornithodoros coriaceus, the probable vector of the causative agent of epizootic bovine abortion, did not cause any untoward reactions in pregnant heifers which were experimentally inoculated or which were exposed to bites of O coriaceus that had been infected with cultures of the two isolates. Seemingly, neither viral isolate is involved in the cause of epizootic bovine abortion.

Abortion, Veterinary

Preliminary studies on transmission of Chlamydia to cattle by ticks (Ornithodoros coriaceus).

Preliminary findings indicate that Ornithodoros coriaceus ticks can harbor Chlamydia for long periods and are able to transmit the agent to cattle. Field-collected O coriaceus ticks, which were infected experimentally with a bovine chlamydial agent from an aborted fetus, transmitted the agent 25 and 48 days later to three pregnant heifers. Two of these heifers aborted and the third delivered a term calf. The control heifer also aborted after intradermal (simulated tick) exposure. Also, a chlamydial agent was isolated from field-collected O coriaceus ticks in an epizootic bovine abortion (EBA)-enzootic area that were held for at least 6 months. In the same enzootic area, a chlamydial agent was isolated from a prematurely delivered calf during a severe EBA outbreak. Seemingly, this species is a cause, if not the cause, of EBA.

Abortion, Veterinary