Terrestrial isopod diversity in the subtropical neotropics: Itapuã State Park, southern Brazil

We analysed species abundance and composition during one year of sampling at Itapuã State Park, a conservation unit in the State of Rio Grande do Sul, southern Brazil. Samples were collected monthly from May 2003 to April 2004 along a 4 km forest trail divided in three transects along the slopes of a small hill. Terrestrial isopods were hand searched by three people for 40 minutes at two sampling sites along each transect, summing 240 minutes of sampling effort per transect per month. Six species distributed in six families were found. The collector curve stabilised when half the samples were taken, demonstrating sampling sufficiency: analytical estimates did not predict more species to be found in the trail. Atlantoscia floridana (van Name, 1940) was dominant in all transects. Abundance varied along the year with a summer and a winter peak, but peaks were not consistent among transects. The first part of the trail, used for ecotourism, was less diverse, had less species (4 as compared to 6 in the other transects), and was thus also less similar in composition.

Geographic variation in ectoparasitic mites diversity in Tadarida Brasiliensis (Chiroptera, Molossidae)

Tadarida brasiliensis (Geoffroy, 1824), the Brazilian free-tailed bat, is an insectivorous bat that occurs from southern United States of America to southern South America. In this study we present the first data on diversity of ectoparasitic mites of T. brasiliensis in Brazil. A compilation and analysis of the studies of mite diversity conducted in different points the geographic distribution this bat species are provided. The mites were collected from March 2010 to November 2011 on 160 T. brasiliensis adult bats captured in southern Brazil. Four species of mites have been found: Chiroptonyssus robustipes (Ewing, 1925), Ewingana longa (Ewing, 1938), Ewingana inaequalis (Radford, 1948), and specimens of Cheyletidae. Chiroptonyssus robustipes was the most prevalent species (100%), followed by E. longa (20%), E. inaequalis (10%), and specimens of Cheyletidae (1.25%). The data currently available show that C. robustipes parasitizes T. brasiliensis throughout its region of occurrence, and this mite is highly prevalent and abundant. The two species of Ewingana accompany the geographical distribution of T. brasiliensis, but with much lower prevalence and abundance.

First Case of Natural Infection in Pigs: Review of Trypanosoma cruzi Reservoirs in Mexico

An epidemiological research project was performed in the State of Morelos including collection of samples for blood smears and culture, serological tests, and xenodiagnoses from a total of 76 domestic and peridomestic mammals. Two strains of Trypanosoma cruzi were isolated by haemocultures; one from a pig (Sus scrofa), the first case of natural infection reported in Mexico, and the other from a dog (Canis familiaris). This study summarizes current information in Mexico concerning confirmed reservoirs of T. cruzi

Genetic Diversity in Natural Populations of New World Leishmania

Our results have shown the wide diversity of parasites within New World Leishmania. Biochemical and molecular characterization of species within the genus has revealed that much of the population heterogeneity has a genetic basis. The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, although occasional bouts of sexual reproduction can not be ruled out. Genetic variation is extensive with some clones widely distributed and others seemingly unique and localized to a particular endemic focus. Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas. Future research using molecular techniques should aim to identify and follow Leishmania types in nature and correlate genetic typing with important clinical characteristics such as virulence, pathogenicity, drug resistance and antigenic variation. The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents.

Cuticular hydrocarbons of Chagas disease vectors in Mexico

Capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, Triatoma dimidiata, T. barberi and Dipetalogaster maxima, domestic vectors of Chagas disease in Mexico. Mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. Major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. Sex-dependant, quantitative differences in certain hydrocarbons were apparent in T. dimidiata.

Genetic diversity in Brazilian populations of Aedes albopictus

Random amplified polymorphic DNA (RAPD) analysis technique was undertaken in Aedes albopictus populations from three states in Brazil, Rio de Janeiro (RJ), Minas Gerais (MG) and Pernambuco (PE), to estimate the level of genetic variability and levels of genetic exchange between populations. Allele and genotype frequencies were measured on 47 RAPD loci. Average observed heterozigosity (Ho) ranged from 0.282 in MG to 0.355 in Casa Forte (PE) population. Genetic distances estimates indicated that RJ and MG were more genetically similar than populations from PE. Genetic variation observed in local Brazilian populations was attributed to genetic drift associated with restricted gene flow in recently established populations.

First record of Lutzomyia evansi (Nuñez-Tovar 1924) in Mexico (Diptera: Psychodidae, Phlebotominae)

The phlebotomine sand fly Lutzomyia evansi is recorded in Mexico for the first time. This species is a suspected vector of Leishmania infantum in other parts of its geographical range and was captured in a focus of American visceral leishmaniasis where the principal vector, Lu. longipalpis sensu lato, was also found. The relative public health importance of the two species in the study area (Chiapas state, Southern Mexico) is discussed.

Blood transfusion and iatrogenic risks in Mexico city: anti-Trypanosoma cruzi seroprevalence in 43,048 blood donors, evaluation of parasitemia, and electrocardiogram findings in seropositive

Iatrogenous transmission of Trypanosoma cruziby blood transfusion was suggested as a potential risk by Pellegrino (1949). Seropositive blood donors in Mexico were first reported in 1978, however, limited information is available due to small sampling, the use of heterogeneous serologic assays, and geographically limited studies. A wide survey carried out in 18 out of the 32 states of Mexico, showed a national mean of 1.6% seropositive among 64,969 donors, ranging from 0.2 to 2.8%. In the present study, we have screened 43,048 voluntary blood donors in a period of five years at the Instituto Nacional de Cardiología I. Chávez, a concentration hospital located in Mexico city which serves mainly the metropolitan area and accepts from all over the country. Standardized ELISA and IIF were used to identify seropositive individuals in addition to hemoculture, PCR and standard 12 lead ECG tests that were applied to a group of seropositive patients (29/161). The result showed a seropositivity of 0.37% (161/43,048). From the group of seropositive individuals 40% (12/29) were potential carriers of T. cruzi at the donation time and 5/29 had subclinical ECG abnormalities. Parasitological tests performed in 70 erythrocyte and platelet fractions from seropositive units (70/161) showed negative results. Our findings strongly support T. cruzi screening in the transfusion medicine practice and identify subclinical heart disease among seropositive blood donors.

Mycobacterium avium restriction fragment lenght polymorphism-IS IS1245 and the simple double repetitive element polymerase chain reaction typing method to screen genetic diversity in Brazilian strains

Simple double repetitive element polymerase chain reaction (MaDRE-PCR) and Pvu II-IS1245 restriction fragment length polymorphism (RFLP) typing methods were used to type 41 Mycobacterium avium isolates obtained from 14 Aids inpatients and 10 environment and animals specimens identified among 53 mycobacteria isolated from 237 food, chicken, and pig. All environmental and animals strains showed orphan patterns by both methods. By MaDRE-PCR four patients, with multiple isolates, showed different patterns, suggesting polyclonal infection that was confirmed by RFLP in two of them. This first evaluation of MaDRE-PCR on Brazilian M. avium strains demonstrated that the method seems to be useful as simple and less expensive typing method for screening genetic diversity in M. avium strains on selected epidemiological studies, although with limitation on analysis identical patterns except for one band.

Serogroups, K1 antigen, and antimicrobial resistance patterns of Aeromonas spp. strains isolated from different sources in Mexico

A total of 221 strains of Aeromonas species isolated in Mexico from clinical (161), environmental (40), and food (20) samples were identified using the automated system bioMérieux-Vitek®. Antisera for serogroups O1 to 044 were tested using the Shimada and Sakazaki scheme. The K1 antigen was examined using as antiserum the O7:K1C of Escherichia coli. Besides, we studied the antimicrobial patterns according to Vitek AutoMicrobic system. Among the 161 clinical strains 60% were identified as A. hydrophila, 20.4% as A. caviae, and 19.25% as A. veronii biovar sobria. Only A. hydrophila and A. veronii biovar sobria were found in food (55 and 90% respectively) and environmental sources (45 and 10% respectively). Using "O" antisera, only 42.5% (94/221) of the strains were serologically identified, 55% (121/221) were non-typable, and 2.5% (6/221) were rough strains. Twenty-two different serogroups were found, O14, O16, O19, O22, and O34 represented 60% of the serotyped strains. More than 50% of Aeromonas strain examined (112/221) expressed K1 encapsulating antigen; this characteristic was predominant among Aeromonas strains of clinical origin. Resistance to ampicillin/sulbactam and cephazolin was detected in 100 and 67% of Aeromonas strain tested for their susceptibility to antibiotics. In conclusion, antibiotic-resistant Aeromonas species that possess the K1 encapsulating antigen and represent serogroups associated with clinical syndrome in man are not uncommon among Aeromonas strains isolated from clinical, food and environmental sources in Mexico.

Chagas disease in Mexico: an analysis of geographical distribution during the past 76 years - A review

Literature from 1928 through 2004 was compiled from different document sources published in Mexico or elsewhere. From these 907 publications, we found 19 different topics of Chagas disease study in Mexico. The publications were arranged by decade and also by state. This information was used to construct maps describing the distribution of Chagas disease according to different criteria: the disease, vectors, reservoirs, and strains. One of the major problems confronting study of this zoonotic disease is the great biodiversity of the vector species; there are 30 different species, with at least 10 playing a major role in human infection. The high variability of climates and biogeographic regions further complicate study and understanding of the dynamics of this disease in each region of the country. We used a desktop Genetic Algorithm for Rule-Set Prediction procedure to provide ecological models of organism niches, offering improved flexibility for choosing predictive environmental and ecological data. This approach may help to identify regions at risk of disease, plan vector-control programs, and explore parasitic reservoir association. With this collected information, we have constructed a data base: CHAGMEX, available online in html format.

Occurrence of hybrids and laboratory evidence of fertility among three species of the Phyllosoma complex (Hemiptera: Reduviidae) in Mexico

In seven studied communities of Western Mexico, triatomine specimens were sympatrically collected, some with atypical morphological characteristics in contrast to pure specimens, which were presumed to be hybrids. More than 200 specimens of Meccus pallidipennis and Meccus longipennis with brown-yellow markings on dorsal connexival segments were collected in Ahuacapán and Quitupan. In La Mesa, more than 60 specimens similar to Meccus picturatus in most morphological characteristics (including size) were collected, although they presented a largely yellowish corium like M. pallidipennis. Interfertility was proven between all of the studied wild hybrid specimens, as well as between all the experimental laboratory hybrids. Two different phenotypes (M. picturatus and M. longipennis) were obtained from crosses between M. picturatus x M. picturatus and M. longipennis x M. longipennis from the three studied localities in state of Nayarit as from La Mesita. Results support the hypothesis that the subspecific ranking of those triatomines may, therefore, be more appropriate because reproductive isolation has not been developed and complete interbreeding was recorded.

Intestinal parasites and genotyping of Giardia duodenalis in children: first report of genotype B in isolates from human clinical samples in Mexico

Giardia duodenalis is one of the most prevalent enteroparasites in children. This parasite produces several clinical manifestations. The aim of this study was to determine the prevalence of genotypes of G. duodenalis causing infection in a region of southeastern Mexico. G. duodenalis cysts were isolated (33/429) from stool samples of children and molecular genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, targeting the triosephosphate isomerase ( tpi ) and glutamate dehydrogenase ( gdh ) genes. The tpi gene was amplified in all of the cyst samples, either for assemblage A (27 samples) or assemblage B (6 samples). RFLP analysis classified the 27 tpi -A amplicons in assemblage A, subgenotype I. Samples classified as assemblage B were further analysed using PCR-RFLP of the gdh gene and identified as assemblage B, subgenotype III. To our knowledge, this is the first report of assemblage B of G. duodenalis in human clinical samples from Mexico.

Sandfly species diversity in association with human activities in the Kani tribe settlements of the Western Ghats, Thiruvananthapuram, Kerala, India

Sandfly prevalence in the Kani tribe settlements of Western Ghats in India was investigated. A total of 1,279 sandflies comprising 17 species was obtained. Sandfly abundance showed a negative correlation (r = -0.97, p = 0.003) with increase in altitudinal ranges from 0-1,000 m. When sandfly samples were grouped according to landscape characteristics of the location, the estimated Shannon-Weiner index (H) and species richness index (S) were high and species evenness index (J) was low in settlements located at 0-300 m altitudinal range. On the contrary, the values of H and J were high, while S was low at 301-600 m altitudinal range. With further increase in altitude, species diversity, S and J were low. Though the relative abundance of sandflies decreased with increase in altitude, the influence of altitudinal variation could not be attributed to determine sandfly diversity, since the number of sampling units were not uniform at all the altitudinal gradients due to nonavailability of suitable resting shelters. Sandfly species showed great aggregation at 0-300 m altitude interval, where not only the number of settlements were maximum (n = 19), but also the environmental conditions favoured sandfly abundance due to the concentration of tribal settlements, human dwellings and his activities.