Chagas disease caused by infection with Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae) is widespread in Mexico, transmitted by various triatomine bugs (Hemiptera: Reduviidae). The only domestic vector in Cuernavaca (population 650 000) is Triatoma pallidipennis (Ståhl) with T. cruzi seroprevalence ranging from 1% to 9% in the resident human population. We surveyed possible risk factors for T. pallidipennis infestation at Cuernavaca (altitude 1200-2200 m) on south-western slopes of the Sierra Madre Occidental. This metropolitan area (with five administrative counties) has rapid urbanization, forested environs and proliferation of 'weekend housing' for visitors from Mexico City, 60 km to the north. To assess factors associated with T. pallidipennis infestation, we first stratified Cuernavaca by altitude and by socio-economic status of population catchment units (PCUs). Within each PCU, one to three blocks were chosen for cluster sampling (three houses/block) and information about Chagas disease was distributed. After obtaining signed consent from householders, representative houses were routinely and opportunistically inspected for T. pallidipennis and surveyed for demographic, economic, physical and other potential risk factors. Of the 1129 houses assessed, T. pallidipennis was found in 4.1% (range 3.0-6.8% per county) and the T. cruzi infection rate was approximately 50% in bugs. Rates of house infestation in poor PCUs were double those in higher socio-economic strata (odds ratio 2.12, confidence interval 1.03-4.3), with >4-fold greater crowding index of T. pallidipennis. The bug density index was inversely correlated with PCU altitude and socio-economic category (altitude of homes being associated with prosperity), while the bug colonization index (presence of nymphs indicating breeding) did not vary significantly across the PCU categories, but did vary according to altitude. Multivariate regression analysis showed that the most significant risk factors associated with T. pallidipennis infestation were lower altitude (linked with lower socio-economic status), garden area >80 m(2), dogs at liberty to enter the house, occurrence of squirrels and opossums around the house, presence of pigs in the surrounding area and having at least one of the adjacent lots empty (unconstructed). Householders who had received information about Chagas disease comprised 33% from infested houses (14/42) but only 15% from non-infested houses (148/984). Hence, the awareness of Chagas disease was significantly associated with having a bug-free house (P < 0.01). When shown specimens of T. pallidipennis, the proportions of householders who recognized them were 78% from infested houses but only 29% of those with uninfested houses. Given the low infestation rates and the high capacity of the population to act appropriately once they have received information regarding this disease and its vector, relevant health education is expected to have a significant impact on triatomine control in this metropolitan area.

Entomopathogenic fungi have been investigated as an alternative tool for controlling various insects, including triatomine vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. Here we tested the pathogenicity and virulence of ten isolates of the fungi Metarhizium spp. and Beauveria bassiana against Rhodnius prolixus and found all of the isolates to be virulent. We used two isolates (URPE-11 Metarhizium anisopliae and ENT-1 Beauveria bassiana) for further screening based on their prolific sporulation in vitro (an important property of fungal biopesticides). We characterized their virulences in a dose-response experiment and then examined virulence across a range of temperatures (21, 23, 27 and 30°C). We found isolate ENT-1 to maintain higher levels of virulence over these temperatures than URPE-11. We therefore used B. bassiana ENT-1 in the final experiment in which we examined the survival of insects parasitized with T. cruzi and then infected with this fungus (once again over a range of temperatures). Contrary to our expectations, the survival of insects challenged with the pathogenic fungus was greater when they had previously been infected with the parasite T. cruzi than when they had not (independent of temperature). We discuss these results in terms of aspects of the biologies of the three organisms. In practical terms, we concluded that, while we have fungal isolates of potential interest for development as biopesticides against R. prolixus, we have identified what could be a critical problem for this biological tool: the parasite T. cruzi appears to confer a measure of resistance to the insect against the potential biopesticide agent so use of this fungus as a biopesticide could lead to selection for vector competence.

Runs of homozygosity (ROH) and signatures of selection are results of selection processes in livestock species that has been shown to affect several traits in cattle. The aim of the current work was to verify the profile of ROH and inbreeding depression in the number of total (TO) and viable oocytes (VO), and number of embryos (EMBR) in Gir Indicine cattle. In addition, we aimed to identify signatures of selection, genes and enriched regions between Gir subpopulations sorted by breeding value for these traits. The genotype file contained 2,093 animals and 420,718 SNP markers. Breeding values used to sort Gir animals were previously obtained. ROH and signature of selection analyses were performed using PLINK software, followed by ROH- and pedigree-based inbreeding (FROH) and search for genes and their functions. A total of 105,327 ROHs were found in Gir cattle. ROHs were separated in classes according to the size, ranging from 1 to 2 Mb (ROH1–2 Mb: 58.17%), representing ancient inbreeding, ROH2–4 Mb (22.74%), ROH4 − 8 Mb (11.34%), ROH8 − 16 Mb (5.51%) and ROH> 16 Mb (2.24%). Putting together our results, we conclude that the increase in general ROH-based and pedigree-based inbreeding significantly decreases TO and VO; however, the way ROH affects the traits vary among chromosomes. In the analysis for signatures of selection, we identified 15 genes from 47 significant genomic regions, indicating differences in populations with high and low breeding value for the three traits.

We investigated the effect of including palm kernel cake (PKC) at the levels of 0, 80, 160 and 240 g kg−1 in the diet of lactating goats on the quality and sensory parameters of Minas Frescal cheese. Twelve goats were used in a triple 4 × 4 Latin square design. The dietary addition of PKC was associated with a reduction in moisture (p = 0.004), which compromised the cheese yield (p = 0.030). The ether extract content showed a quadratic response. There was a decrease in caproic (p = 0.014), caprylic (p = 0.011), capric (p = 0.003) and palmitic (p = 0.049) acids and an increase in lauric (p = 0.012) and myristic (p = 0.02) acids. Monounsaturated fatty acids increased (p = 0.008), whereas the ratio of polyunsaturated to saturated fatty acids (p = 0.022) and thrombogenicity index (p = 0.023) decreased. Principal component analysis indicated that control treatment and the treatment with 80 g kg−1 PKC were the most acceptable to the cheese tasters. The use of palm kernel cake is a good alternative for lactating goats when added to the diet at levels up to 80 g kg−1.

Runs of homozygosity (ROH) and signatures of selection are results of selection processes in livestock species that has been shown to affect several traits in cattle. The aim of the current work was to verify the pro le of ROH and inbreeding depression in the number of total (TO) and viable oocytes (VO), and number of embryos (EMBR) in Gir Indicine cattle. In addition, we aimed to identify signatures of selection, genes and enriched regions between Gir subpopulations sorted by breeding value for these traits. The genotype le contained 2,093 animals and 420,718 SNP markers. Breeding values used to sort Gir animals were previously obtained. ROH and signature of selection analyses were performed using PLINK software, followed by ROH-and pedigree-based inbreeding (F ROH ) and search for genes and their functions. A total of 105,327 ROHs were found in Gir cattle. ROHs were separated in classes according to the size, ranging from 1 to 2 Mb (ROH 1-2 Mb : 58.17%), representing ancient inbreeding, ROH 2-4 Mb (22.74%), ROH 4 − 8 Mb (11.34%), ROH 8 − 16 Mb (5.51%) and ROH > 16 Mb (2.24%). Putting together our results, we conclude that the increase in general ROH-based and pedigree-based inbreeding signi cantly decreases TO and VO; however, the way ROH affects the traits vary among chromosomes. In the analysis for signatures of selection, we identi ed 15 genes from 47 signi cant genomic regions, indicating differences in populations with high and low breeding value for the three traits.

Our objective was to establish a SNPs panel for pedigree reconstruction using chips of different densities and evaluate the genomic relationship coefficient of the inferred pedigree, in addition to analyzing the population structure based on genomic analyses in Gir cattle. For parentage analysis and genomic relationship, 16,205 genotyped Gir animals were used being 14,458 females and 1,747 males, and 1,810 common markers to the four SNP chips. For population structure analyses, which include linkage disequilibrium, effective population size, and runs of homozygosity (ROH), the genotypes of 21,656 animals were imputed. The likelihood ratio (LR) approach was used to reconstruct the pedigree. The LR approach deepened the pedigree and showed that it is well established in terms of recent information for this breed. The coefficients for each 2 relationship category of the inferred pedigree were adequate. Linkage disequilibrium showed rapid decay. We detected a decrease in the effective population size over the last 50 generations, with the average generation interval estimated at 9.08 years. A higher ROH-based inbreeding coefficient in a class of short segments of ROH, with moderate to high values was also detected, suggesting the presence of bottlenecks in the Gir cattle genome. Breeding strategies to minimize inbreeding and avoid massive use of a few proven sires with high genetic value are suggested to maintain genetic variability in future generations. In addition, we recommend reducing the generation interval to maximize genetic progress and increase effective population size.

Our objective was to establish a SNPs panel for pedigree reconstruction using chips of different densities and evaluate the genomic relationship coefficient of the inferred pedigree, in addition to analyzing the population structure based on genomic analyses in Gir cattle. For parentage analysis and genomic relationship, 16,205 genotyped Gir animals were used being 14,458 females and 1,747 males, and 1,810 common markers to the four SNP chips. For population structure analyses, which include linkage disequilibrium, effective population size, and runs of homozygosity (ROH), the genotypes of 21,656 animals were imputed. The likelihood ratio (LR) approach was used to reconstruct the pedigree. The LR approach deepened the pedigree and showed that it is well established in terms of recent information for this breed. The coefficients for each relationship category of the inferred pedigree were adequate. Linkage disequilibrium showed rapid decay. We detected a decrease in the effective population size over the last 50 generations, with the average generation interval estimated at 9.08 years. A higher ROH-based inbreeding coefficient in a class of short segments of ROH, with moderate to high values was also detected, suggesting the presence of bottlenecks in the Gir cattle genome. Breeding strategies to minimize inbreeding and avoid massive use of a few proven sires with high genetic value are suggested to maintain genetic variability in future generations. In addition, we recommend reducing the generation interval to maximize genetic progress and increase effective population size.

No abstract