Sequential feedings by two species of argasid tick on laboratory mice: effects on tick survival, weight gain, and attachment time.

Preliminary observations made during colony maintenance of argasid ticks led us to suspect that the host immune response of laboratory mice being used for tick feeding might be causing increased tick mortality. Sequential feeding trials were conducted on laboratory mice using fast- and slow-feeding Ornithodoros larvae. Acquired host resistance was demonstrated. With the fast-feeding O. turicata (Dugès), the average amount of weight gained during feeding decreased significantly the second and third times larvae were exposed to the same mice. With the slow-feeding O. talaje (Guérin-Méneville), mortality at the second and third exposure significantly increased when compared with that seen upon naive mice. Implications for natural modulation of argasid tick populations resulting from nearly constant host exposure to ticks of this nature are also discussed.

Possible applications of the immune response of laboratory mice to the feeding of argasid ticks.

Immunization of CD1 mice with various crude extracts of argasid tick parts in two different adjuvants induced high host IgGl antibody levels that could be detected in the hemolymph of recently fed argasid ticks. In the case of the fast feeding Ornithodoros turicata (Dugés), host immunization had no immediate effect on tick survival. In the case of the longer feeding species O. talaje (Gueín-Meneville), it induced a significant (P less than 0.05) 32% reduction in tick survival comparable to that of naturally acquired resistance.

Cellular responses of laboratory mice to feedings of Ornithodoros talaje (Acari: Argasidae) larvae.

Studies were carried out in which laboratory mice were subjected to sequential feedings by slow feeding Ornithodoros talaje (Guerín-Méneville) larvae to detect and characterize the host cellular response. After the first exposure, histological evidence showed a strong neutrophil infiltration at the site of attachment and feeding. By the third exposure, a marked shift to lymphocytes was noted in the mouse tissues using histological preparations of the feeding ticks. Lymphocyte proliferation tests also provided indirect evidence of a host lymphocyte response as a result of the three tick exposures and feedings.

Annotated list of ticks (Acari: Ixodidae, Argasidae) reported in Peru: distribution, hosts, and bibliography.

A literature review and compilation of the tick specimens found in Peru and now held in the National Tick Collection was carried out to develop a working list of the tick species likely to be found in Peru. Evidence of 44 species (29 Ixodidae, 15 Argasidae), was found; representatives of 40 species are held as reference specimens. This report adds 14 species to the previously published list.

Antibody responses of laboratory mice to sequential feedings by two species of argasid ticks (Acari: Argasidae).

The host antibody response of CD1 mice resulting from sequential exposures to two species of Ornithodoros ticks was isotyped (ELISA) in an effort to determine the mechanism for the development of acquired resistance. In addition, salivary gland proteins from two argasid and one ixodid species were examined (RIA) for cross-reactivity. Significant antibody responses, detectable for at least 90 d after last exposure, were shown to occur. Isotyping showed that the initial response was of the IgM class with a secondary class switch to the IgG1 subclass occurring. Evidence that cross-reactive proteins exist between argasid and ixodid ticks is also discussed.

Isolation and characterization of mouse monoclonal antibodies reactive with soft tick (Acari: Argasidae) salivary antigens of high molecular weight.

The purpose of this study was to immunologically characterize soft tick salivary antigens. BALB/c mice hyperimmunized with salivary gland extract prepared from Ornithodoros talaje (Guérin-Méneville) were observed to develop high titers of antitick salivary antigen antibodies. Subsequent fusion of splenic lymphocytes from the hyperimmunized mice with SP-2/0-AG14 myeloma cells resulted in the production of 10 antitick IgM-producing hybridoma clones. Partial characterization of the respective tick antigens by gel filtration and SDS-PAGE demonstrated all 10 monoclonal antitick antibodies to be reactive with a salivary gland extract fraction containing proteins 50-110 kDa in molecular weight. Cross-reactivity assays and electrophoretic comparison of salivary gland extract specimens demonstrated similar proteins in several ixodid tick genera and species.

Mosquitoes (Diptera: Culicidae) captured in the Iquitos area of Peru.

A mosquito capture program was initiated to study mosquito species and their potential for arboviral transmission in the Peruvian Amazon. More than 35,000 mosquitoes of 13 different genera and at least 25 species were captured in urban and sylvan sites in the Iquitos area. These findings represent the first published list of Peruvian mosquitoes since 1971 and the first such list from the Peruvian Amazon.

Plasmodium vivax VK247 and VK210 circumsporozoite proteins in Anopheles mosquitoes from Andoas, Peru.

Anopheles mosquitoes captured in Andoas, Peru, a Plasmodium vivax-endemic area in the Peruvian Amazon region, contained both VK210 and VK247 P. vivax circumsporozoite (CS) proteins. Approximately 0.9% of the 4,403 mosquitoes tested by enzyme-linked immunosorbent assay were positive; 28% and 72% of the positive mosquitoes contained VK210 and VK247 CS proteins, respectively. These findings correlate strongly with a recent report of the presence of antibodies in residents of this area that recognize the VK210 and VK247 repeats, clearly indicating that both P. vivax CS protein polymorphs are common in the region.