The relationship between ovarioles number and female size in blackflies of the high Andes of Colombia

Fitness of a single species is often measured in terms of the number of viable offspring produced. We explore the relationship between the number of ovarioles and the size of females in five species of Simuliidae in two páramo regions of Colombia. Individuals of seven species of female blackflies that landed on animals were collected from mules in the Ucumarí Regional Park (RPNU) and from cattle in the Chingaza Natural National Park (ChNNP). The ovarioles of the five most abundant species were dissected out and counted, and a one-factor ANOVA was performed to explore differences in the mean number of ovarioles produced by different female size categories. Simulium ignescens Roubaud and S. ignescens-like species were collected in RPNU and S. ignescens, Simulium muiscorum Bueno et al, Simulium cormonsi Wygodzinsky and Simulium pautense Coscarón & Takaoka, in ChNNP. In addition, we also analyzed the Pearson product-moment correlation between the mean number of ovarioles per blackfly and female size within species using those which more than 20 individuals were collected. Ovarioles were meroistic-polytrophic type. A multiple range test (least significant difference) indicated that the largest size group had the largest mean number of ovarioles per female. In the other size groups, there were approximately equal numbers of ovarioles per female. Pearson's correlation coefficient was separately measured and indicated a 50% correlation between female size and ovariole number in S. ignescens. Although ovariole number is probably a genetically driven feature, other environmental and physiological conditions, including infections, can influence the number of eggs.

Leishmania (Viannia) guyanensis induces low immunologic responsiveness in leishmaniasis patients from an endemic area of the Brazilian Amazon Highland

Cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis (CL-Lguy) is endemic in the Brazilian Amazon, differing from L. braziliensis infection in clinical, diagnostic, and therapeutic aspects. T-cell reactivity to leishmanial antigens possibly involved in the pathogenesis of CL-Lguy was studied herein. Variable lymphoproliferative responses (LPRs) to Leishmania antigens were found among the 23 studied patients, and 50% of them showed low or no response to these antigens. Active disease was associated with an enrichment of leishmanial-reactive T lymphocytes, mainly TCD4(+). High and low interferon (IFN)-gamma producers were observed. TNF-alpha, interleukin (IL)-10, and IL-5 were consistently detected. CL-Lguy displayed low antibody response in comparison to L. braziliensis patients. CL caused by L. braziliensis presented positive LPRs and higher IFN-gamma production but undetectable IL-5. L. guyanensis seems to induce a down-regulation of the immune system compared with L. braziliensis. This finding could explain some aspects of clinical presentation of CL-Lguy, such as high tissue parasite burden and frequent resistance to therapy.

Blood parasites in some birds from eastern plains of Colombia

A total of 315 birds representing 75 species (23 families) from Villavicencio and San Miguel (Meta, Colombia) were examined for haematozoa. Fifty birds (15.9%) harbored blood parasites. Microfilariae were the most common haematozoans encountered, followed by species of the genera Haemoproteus, Plasmodium and Trypanosoma. This survey included 15 new host-parasite records and 8 species of birds that were examined for haematozoa for the first time. The prevalence registered in this research was similar to others recorded in the Neotropical region, but in sharp contrast with the prevalence of blood parasites in other major land masses.