No abstract

The diagnosis of tick-borne diseases such as babesiosis still depends on observing the parasite in the infected erythrocyte. Microscopic observation is tedious and often problematic in both early and carrier infections. Better diagnostic methods are needed to prevent clinical disease, especially when susceptible cattle are being moved into disease enzootic areas. This study evaluates two techniques for early diagnosis of Babesia bovis infections in cattle, DNA probes specific for the organism and fluorescent probes specific for nucleic acid. The radioisotopically labeled DNA probes are used in slot blot hybridizations with lysed blood samples, not purified DNA. Thusfar, the probe is specific for B. bovis and can detect as few as 1000 B. bovis parasites in 10 microliters of blood. The specificity of the fluorescent probe depends on the characteristic morphology of the babesia in whole blood samples, as determined microscopically. The fluorescent probe detects as few as 10,000 B. bovis parasites in 10 microliters os blood. The application of each method for laboratory and field use is discussed.

Babesia equi, a causative agent of equine piroplasmosis, was isolated from horses in the Chaco Province of Argentina, a known piroplasmosis endemic region. Fifteen B. equi field isolates were acquired by culture from 23 actively working horses from 2 ranches. The horses appeared healthy with no clinical signs or histories indicative of equine piroplasmosis. All 23 horses had B. equi-specific antibody activity by the indirect fluorescent antibody test and 18 were also complement fixation test positive for B. equi. Equine erythrocytes were prepared for parasite culture using a microcentrifuge tube method. This method greatly reduces the time involved in cell handling and parasite exposure to ambient conditions. By this method, B. equi cultures can be initiated from very small quantities of blood.

Seasonal abundance of ectoparasites was estimated from monthly collections of Eastern (Sturnella magna (L.)) and Western (Sturnella neglecta Audubon) meadowlarks in Starr County, Tex. Ecological relationships of ticks, Amblyomma maculatum Koch, Amblyomma inornatum (Banks), and Haemaphysalis leporispalustris (Packard) (Acari: Ixodidae); lice, Menacanthus sturnellae Price (Mallophaga: Menoponidae) and Bruelia picturata (Osburn) (Mallophaga: Philopteridae); and louse fly, Microlynchia pusilla (Speiser) (Diptera: Hippoboscidae) are discussed. New host records are noted for A. inornatum, M. sturnellae, and a single specimen of Columbicola macrourae (Wilson) (Mallophaga: Philopteridae) from an Eastern meadowlark. Recovery of three genera of astigmatid mites, one genus of prostigmatid mites, and three genera of mesostigmatid mites is mentioned. KEY WORDS Arachnida, Sturnella, ectoparasites, abundance ADULT GULF COAST TICKS, Amblyomma maculatum Koch, are an annual pest of cattle in areas of

Two morphologically dissimilar Babesia spp. were cultured from reindeer (Rangifer tarandus tarandus) in Placer County, Calif. The smaller isolate, designated RD61, was morphologically similar to Babesia odocoilei. Serum from RD61-infected reindeer reacted equally strongly to B. odocoilei and RD61 parasites in the indirect fluorescent antibody (IFA) test. Small subunit ribosomal RNA (SSU rRNA) gene-sequence analysis showed 99.0% identity to that of B. odocoilei. The larger piroplasm, designated RD63, resembled larger babesia organisms, such as Babesia caballi and Babesia bigemina. Serum from RD63-infected reindeer also reacted with both B. odocoilei and RD61 parasites in the indirect fluorescent antibody test. The SSU rRNA gene showed 94.2% identity to that of B. bigemina. Further studies are needed to determine whether these parasites are the same as the Babesia spp. previously documented in Siberian reindeer.