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Cryptosporidium parvum coproantigens (CCAg) of 18 and 20 kDa were identified in the stool eluates of calves and humans infected with Cryptosporidium species. Monospecific antibodies raised against the 20-kDa antigen recognized both 18- and 20-kDa CCAg in all positive but no negative control samples. These antibodies reacted with C. parvum sporozoites in an immunofluorescence assay. Human immune sera recognized the 20-kDa antigen in infected calf stool eluates. Both 18- and 20-kDa CCAg remained intact in commonly used preservatives and at various temperatures. These CCAg may be useful in designing sensitive, reliable methods for diagnosing cryptosporidiosis.

Pupae of Culex quinquefasciatus Say from a laboratory colony were sterilized when 20 to 26 h old by immersion in bisazir [ P, P -bis (l-aziridinyl)- N -methyl phosphinothioic amide] solution, by gamma irradiation, or by combinations of substerilizing treatments of both. Greater than 99% male sterility was achieved when pupae were irradiated at ca. 8 kR or immersed in 1% bisazir solution for 30 min. Combinations of radiation and chemical sterilization, each at substerilizing levels, produced levels of sterility expected for an additive relationship between the two sterilizing agents. The empirical relationship between sterility (S) and the two sterilizing agents was characterized by the formula: S = −7.73 + 9.76 B + 14.36 K −1.44 BK − 0.06 B2 + 0.44 K2, where B = minutes of exposure to bisazir and K = radiation dose in kR. Males sterilized by bisazir were fully (96%) competitive under laboratory conditions, whereas males sterilized by treatments involving irradiation (26%) or a combination of bisazir and irradiation (15%) were less competitive.

Male sterility and sexual competitiveness were evaluated after irradiation (Cesium-137 source) of 20- to 26-h-old pupae and 0- to 20-h-old adults of Culex quinquefasciatus Say in air and nitrogen (N2. The presence of nitrogen protected both stages against the induction of posttreatment sterility. In nitrogen, the exposure required for 98% sterility had to be increased from 8 kR in air to 20 kR. At lower irradiation dosages, nitrogen offered more protection of genetic tissues for pupae than adults. However, no improvement was observed in the mating competitiveness when air was replaced with nitrogen during pupal irradiation, and only marginal improvement was observed after adult exposure. Because of its deleterious effect on male competitiveness, irradiation may have limited usefulness as a method of sterilization for this species.