Morphometric and phenetic studies of five geographical populations of Lutzomyia whitmani (Diptera: Psychodidae) in Brazil

A morphometric survey examined adult specimens of Lutzomyia whitmani (Antunes & Coutinho) captured at 5 municipalities in southeastern and northeastern Brazil to compare the populations. The localities were Ilhéus (Bahia), Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), Baturité (Ceará), and Amaraji (Pernambuco): all are known foci of American cutaneous leishmaniasis. Fifteen males and 15 females from each population were analyzed morphometrically for 42 and 37 characters, respectively. Statistical data alone were insufficient to discriminate among the 5 populations. Further analysis generated phenograms that indicated there were 2 spatial clusters: the 1st was composed of specimens from Ilhéus (Bahia) and Baturité (Ceará) and the 2nd of specimens from Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), and Amaraji (Pernambuco). Although insufficient to define the taxonomic status of the populations studied, the results delineated the existence of biogeographical structuring within L. whitmani. Complementary studies on the susceptibility to Leishmania braziliensis infection in the 5 populations are in progress to clarify the relationship between the 2 biogeographical clusters and American cutaneous leishmaniasis transmission in those Brazilian regions.     

TNF, IFNG, IL6, IL10 and TGFB1 gene polymorphisms in South and Southeast Brazil

This study attempted to establish single nucleotide polymorphism frequencies of TNF, IL6, IFNG, IL10 and TGFB1 genes among healthy individuals from South and Southeast Brazil. The sample included 108 healthy individuals from South and 106 from Southeast Brazil. Polymerase chain reaction using sequence-specific primers genotyping was performed for these gene cytokines with Cytokine Genotyping Primers (One Lambda, Canoga Park, CA, USA). Differences in genotypic and allelic frequencies between the populations were assessed by chi-square with either Yates' correction or Fisher's exact test. Our investigations showed that there were not any significant differences between these two Brazilian populations for these polymorphisms. A statistically significant difference in the distribution of alleles and genotypes for both IL6 and IL10 genes was observed between the Brazilian population and the African-derived populations. IL6-174GG genotype and allele G and IL10-819CT/-592CA genotypes are more frequent in African-derived populations than in this mixed Brazilian population, while IL10-1082GG genotype is more frequent in our population. This mixed Brazilian population is closer to those of Joinville's, Santa Catarina, and Rio de Janeiro's, Rio de Janeiro (RJ), Euro-Brazilian populations than to those of Salvador's, Bahia, and Rio de Janeiro's, RJ, African-Brazilian populations. These findings have an enormous importance for experimental design and empowering future linkage and association mapping studies of the role of cytokines in human diseases and allotransplantation outcome in Brazil.     

Genetic variability of Triatoma brasiliensis (Hemiptera: Reduviidae) populations

Isoenzymes, random amplified polymorphic DNA (RAPD), and morphometry were used to compare genetic variability within and between three populations of Triatoma brasiliensis Neiva, 1911 from northeast Brazil. The isoenzyme profiles were identical for the three populations, whereas the complex RAPD patterns allowed clear discrimination between the three. Morphometric analysis, using characters of the head capsule, also showed discrimination between the three populations but only in comparisons of males, not females. The results show considerable genetic heterogeneity in T. brasiliensis, with an indication of geographic structuring possibly resulting from a recent series of domestication events.     

New records and laboratory-rearing data for Ixodes schulzei (Acari: Ixodidae) in Brazil

Ixodes schulzei Arag?o and Fonseca was described from Brazil in 1951 based on female ticks collected on wild rats from the states of Rio de Janeiro and Santa Catarina. Since that time, there have been no additional reports of I. schulzei in the literature. We report two new records of I. schulzei: a female collected on the water rat Nectomys squamipes (Brants) from Minas Gerais State, and another female from this same host species from S?o Paulo State. This last specimen was engorged and oviposited fertile eggs in the laboratory. Larvae hatched from these eggs were used for subsequent infestations under laboratory conditions, as were nymphs obtained from the engorged larvae. Naive laboratory rats (Rattus norvegicus Berkenhout) and wild mice (Calomys callosus Rengger) were used to feed ticks. C. callosus was a more suitable host than R. norvegicus, as significantly more ticks (P < 0.05) were recovered and successfully molted after feeding on the former host species. A significantly (P < 0.05) greater proportion of larvae detached from C. callosus during daylight (71.3%) when compared with those that detached from R. norvegicus in the same period (54.8%). A total of nine engorged nymphs (one from R. norvegicus, and eight from C. callosus) were recovered in the infestations. All of them successfully molted to adults, which were all females. The male of I. schulzei remains unknown.     

Physical growth of schoolchildren from the Jequitinhonha Valley,Minas Gerais,Brazil: Comparison with the CDC-2000 reference using the LMS method

Abstract

Objective: To analyse the physical growth of a representative school population sample from the Jequitinhonha Valley, Minas Gerais, Brazil, in comparison with the reference proposed by the Centre for Disease Control and Prevention (CDC-2000).

Methods: The sample was composed of 5100 individuals (2730 girls and 2370 boys), aged 6–18 years. Body weight-for-age and height-for-age percentiles were obtained using the LMS method. Statistical and graphical comparisons were made with the corresponding percentiles of the CDC-2000 reference, estimated using the same method.

Results: Overall, the calculated values of the L (asymmetry) and the S (variability) parameters were quite similar to the CDC-2000 reference values. However, M (median) was substantially different from the reference used in the study, mainly in schoolchildren over 12–13 years of age of both genders. The magnitude of the deficits of height-for-age and body weight-for-age observed in the schoolchildren from the Jequitinhonha Valley, Minas Gerais, Brazil, varied from 4 to 6 cm and from 3 to 6 kg, respectively.

Conclusion: The body weight-for-age and height-for-age percentiles of schoolchildren population in the Jequitinhonha Valley, Minas Gerais, Brazil differed substantially from those referenced.     

Metric variation among geographic populations of the Chagas vector Triatoma dimidiata (Hemiptera: Reduviidae: Triatominae) and related species

Eight Triatoma dimidiata populations from different geographic regions were compared along with related species using traditional morphometry of head characters. A method for removing allometric change was used for the intraspecific comparisons, and scaling for the isometric change of size was used for the interspecific comparisons. The intraspecific comparison showed significant head shape differences between T. dimidiata populations correlating with geography, showing a separation between the northern, intermediate, and southern collections (more evident in females), and supporting the idea that this species includes several evolutionarily divergent populations. The positioning of one sylvatic group from Guatemala did not correlate with geography, because it was more closely related to a distinct population of Colombia. This sylvatic group was found in caves, while the Colombian specimens, although collected in houses, may have migrated from nearby caves. Evolutionary and/or ecological influences could be responsible for the head shape similarities between these two groups: a common ancestral origin of both populations or a morphological convergence caused by similar environmental pressures. The interspecific comparisons included four other regional species of the same genus, three of them belonging to the phyllosoma complex (T. pallidipennis, T. mexicana, and T. ryckmani, the latter provisionally) and the fourth one classified in the protracta complex (T. nitida). Both complexes were readily separated by their head dimensions, even after size adjustment, and our data support inclusion of T. dimidiata within the phyllosoma complex.     

Notes on ectoparasites of some small mammals from Santa Catarina State, Brazil

A small collection of mammals, including 34 individuals from Santa Catarina State, was examined for ectoparasites. One species of tick, eight species of mites, one species of sucking louse, one species of biting louse, and one species of flea are recorded for the first time from Santa Catarina. New host records are given for two species of Acari, one of louse, and one of flea. Species that occurred in single or multiple infestations are recorded.     

Establishment of Tunga trimamillata (Siphonaptera: Tungidae) in Brazil

Tunga trimamillata is a species of sand flea occurring in Ecuador and Peru parasitizing cattle, goat, sheep, swine, and man. This is the first report of this species in Brazil, having been found on the hooves of cows in Barretos, São Paulo State, and Felixlândia, Minas Gerais State, and previously misidentified as Tunga penetrans. A previous report concerning Hydrochoerus hydrochaeris from Rio Novo, Minas Gerais State, may also be attributed to that species of sand flea, a possible the primary host. Given the large geographical distribution of T. trimamillata, the vast cattle population in Brazil, and the high number of individuals subject to the risk of tungiasis, the number of cases attributed to this sand flea will most likely increase over time.     

A fourth chemotype of Lutzomyia longipalpis (Diptera: Psychodidae) from Jaibas, Minas Gerais State, Brazil

Lutzomyia longipalpis (Lutz and Neiva) is a species complex of Lutzomyia pseudolongipalpis (Arrivillaga and Feliciangeli) and at least three other as yet undefined siblings. Isozyme and mitochondrial studies of allopatric populations across Central and South America have suggested the presence of four "clades" that have been hypothesized to have arisen mainly because of geographical isolation mechanisms. Parallel studies of sexual behavior as well as cross-mating and genetic analysis, of both allopatric and sympatric populations, suggest at least four sibling species that do not seem to correspond to the defined four "clades." In an effort to understand this apparent discrepancy, sympatric populations of L. longipalpis from a single South American country, Brazil, are being studied. In Brazil, three putative species can be identified by their male-produced sex pheromones: (S)-9-methylgermacrene-B, 3-methyl-a-himachalene, and a cembrene. We report here that analysis by coupled gas chromatography-mass spectrometry shows that L. longipalpis from Jaibas, Minas Gerais State, Brazil, occurs as two sympatric sex pheromone chemotypes. One chemotype is the cembrene type previously recorded in a L. longipalpis population from Sobral, Ceará State, Brazil, and the other is a new cembrene isomer not previously observed in L. longipalpis. The finding of this new chemotype strongly suggests that the L. longipalpis species complex in Brazil consists of four members rather than the three previously recognized and confirms previous analysis of genetic variation that had suggested the presence of a complex in Brazil.     

Schizodeme and zymodeme analysis of trypanosomes of the subgenusSchizotrypanum from the bat

Two stocks and nine clones of trypanosomes of the subgenusSchizotrypanum were analyzed based on their electrophoretic pattern ofEcoR1 digestion products of kinetoplast DNA (k-DNA) minicricles (schizodeme) and isoenzymes (zymodeme). The trypanosome stocks were isolated fromPhyllostomus hastatus bats collected in different locations in Minas Gerais State, Brazil. The k-DNA pattern showed major variations between stocks and microvariations among the clones. Furthermore, in one of several cloning attempts, two different populations could be isolated. Among the six enzymes studied, glucose phosphate isomerase presented different patterns for stocks and clones. No similarity was found among bat trypanosomes andTrypanosoma (Schizotrypanum) cruzi standard zymodemes. This shows that bat trypanosomes are distinct fromT. (S.) cruzi.     

Intraspecific variation of second internal transcribed spacer of nuclear ribosomal DNA among populations of Anopheles (Kerteszia) cruzii (Diptera: Culicidae)

Anopheline species of the subgenus Kerteszia, including Anopheles (Kerteszia) cruzii Dyar & Knab (Diptera: Culicidae), are bromeliad-malaria vectors in the Atlantic rain forest of Brazil. Morphological, genetic, and molecular polymorphisms among different populations of An. cruzii have been reported, and it has been suggested that this taxon includes a complex of cryptic species. Specimens of An. cruzii were collected in the states of SHo Paulo and Santa Catarina, from locations where autochthonous malaria cases have been reported during the last decade. The second internal transcribed spacers (ITS2) of nuclear ribosomal DNA of the captured specimens were sequenced and compared with each other. Intraspecific ITS2 sequence polymorphisms were identified, and nucleotide divergence among specimens varied from 0.3 to 0.9%. The number of nucleotides in the ITS2 sequences of these mosquitoes varied from 327 to 334, and the CG contents varied from 61.7 to 62%. The data provide further indication of An. cruzii being a complex of cryptic species.     

PKU in Minas Gerais State,Brazil: Mutation Analysis

This work was undertaken in order to ascertain the PKU mutational spectrum in Minas Gerais, Brazil, the relative frequency of the mutations in the State and the origin of these mutations by haplotype determination. Minas Gerais is a trihybrid population formed by miscegenation from Europeans, Africans and Amerindians. All 13 exons of the PAH gene from 78 PKU patients were analyzed, including splicing sites and the promoter region. We identified 30 different mutations and 98% of the PAH alleles were established. A new mutation (Q267X) was identified as well. The most common mutations found were V388M (21.2), R261Q (16.0%), IVS10‐11G>A (15.3%), I65T (5.8%), IVS2+5G>C (5.8%), R252W (5.1%), IVS2+5G>A (4.5%), P281L (3.8%) and L348V (3.2%). These nine mutations correspond to 80% of the PKU alleles in the state. Haplotypes were determined to characterize the origin of the PAH alleles. The majority of the mutations found, with respective haplotypes, are frequent in the Iberian Peninsula. However, there were some mutations that are rare in Europe and four previously unreported mutation‐haplotype associations. I65T and Q267X were found in association with haplotype 38 and may be African in origin or the result of miscegenation in the Brazilian population.     

Molecular variability of cowpea mild mottle virus infecting soybean in Brazil

Molecular variability was assessed for 18 isolates of cowpea mild mottle virus (CPMMV, genus Carlavirus, family Betaflexiviridae) found infecting soybean in various Brazilian states (Bahia, Goiás, Maranhão, Mato Grosso, Minas Gerais, Pará) in 2001 and 2010. A variety of symptoms was expressed in soybean cv. CD206, ranging from mild (crinkle/blistering leaves, mosaic and vein clearing) to severe (bud blight, dwarfing, leaf and stem necrosis). Recombination analysis revealed only one CPMMV isolate to be recombinant. Pairwise comparisons and phylogenetic analysis were performed for partial genomes (ORF 2 to the 3’ terminus) and for each ORF individually (ORFs 2 to 6), showing the isolates to be distinct. The topology of the phylogenetic tree could be related to symptoms, but not to the year of collection or geographical origin. Additionally, the phylogenetic analysis supported the existence of two distinct strains of the virus, designated CPMMV-BR1 and CPMMV-BR2, with molecular variations between them.     

Random amplified polymorphic DNA profiles of Trypanosoma cruzi isolates from chagasic patients with different clinical forms

The genetic variability of 61 Trypanosoma cruzi isolates from 47 chronic chagasic patients of Minas Gerais state was analyzed by random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) using M13-40, λgt11-F, and L15996 primers. Cluster analysis by unweighted pair group method analysis was applied to RAPD profiles, and cluster analysis used to verify a possible correlation among different clinical forms of the disease from these patients. The T. cruzi isolates showed distinct grouping on tree topology, with the isolates not being possible to establish a correlation to the clinical forms of Chagas’ disease. These data showed that the T. cruzi isolates from these patients would compose a group of populations well correlated genetically.     

Bat flies (Diptera: Streblidae, Nycteribiidae) and mites (Acari) associated with bats (Mammalia: Chiroptera) in a high-altitude region in southern Minas Gerais, Brazil

A total of 71 bat flies belonging to families Nycteribiidae and Streblidae, and 37 mites were collected on 12 species of bats (Phyllostomidae and Vespertilionidae) from the Chapada do Abanador (Minas Gerais, Brazil), between July 2009 and April 2010. Two new occurrences of ectoparasites were recorded on Histiotus velatus (bat fly Basilia producta) and on Carollia perspicillata (mite Parichoronyssus bakeri). Five new occurrences were recorded for the state of Minas Gerais, increasing the range for bat flies Anatrichobius passosi, Paraeuctenodes similis, Basilia juquiensis, Basilia producta and for mite Periglischrus vargasi. Moreover, two new species of mites were recorded for Brazil (P. bakeri and Macronyssus aff. leislerianus). With regard to infracommunities, the most frequent association was between Anastrebla modestini and Exastinion clovisi on bat Anoura geoffroyi. This study contributed to characterize the fauna of bat ectoparasites in representative but poorly-sampled environments of the Atlantic Forest, the campos de altitude (high altitude grasslands) and cloud forests of southern Minas Gerais.     

Inbreeding effect on morbidity: IV. Further data in Brazilian populations

The analysis of the data on 5677 children of 1063 couples from a fourth sample of consanguineous and nonconsanguineous marriages among whites and nonwhites living in the State of Minas Gerais, Brazil led to the following estimates: B (number of abnormal equivalents per gamete) around 0.5; A (morbidity in the non-inbred subsamples) 2–3 percent; B/A 13, 15, and 27 (this suggests that the morbidity disclosed by inbreeding may predominantly represent a mutational load): RR ( relative risk) about 2 (this means that among the children of consanguineous marriages there is about double the frequency of abnormalities than in those with nonconsanguineous marriages); AR (attributable risk) for the whole sample about 7% (5% for nonwhites and and 15% for whites). These last valuse show the amount that the frequency of abnormalities would decrease in the population in the risk factor (consanguineous marriages) would be eliminated. AR is higher in whites because the frequency of the risk factor is higher among whites.     

Inbreeding effect on morbidity: IV. Further data in Brazilian populations.

The analysis of the data on 5677 children of 1063 couples from a fourth sample of consanguineous and nonconsanguineous marriages among whites and nonwhites living in the State of Minas Gerais, Brazil led to the following estimates: B (number of abnormal equivalents per gamete) around 0.5; A (morbidity in the non-inbred subsamples) 2-3 percent; B/A 13, 15, and 27 (this suggests that the morbidity disclosed by inbreeding may predominantly represent a mutational load); RR (relative risk) about 2 (this means that among the children of consanguineous marriages there is about double the frequency of abnormalities than in those with nonconsanguineous marriages); AR (attributable risk) for the whole sample about 7% (5% for nonwhites and 15% for whites). These last values show the amount that the frequency of abnormalities would decrease in the population if the risk factor (consanguineous marriages) would be eliminated. AR is higher in whites because the frequency of the risk factor is higher among whites.     

Study of phlebotomine sand flies (Diptera: Psychodidae) collected in a Leishmania-endemic area of the metropolitan region of Belo Horizonte, Brazil

Phlebotomine sand flies are distributed across nearly all faunal regions of the world, represented by over 800 species, of which many are important vectors of human pathogens. Brazil is currently faced with the expansion and urbanization of leishmaniases, with an increase in the numbers of human cases and seropositive dogs in various medium-sized to large cities. The objective of the current study was to survey the phlebotomine sand fly species in an area endemic for American cutaneous leishmaniasis (ACL) and American visceral leishmaniasis (AVL), i.e., the municipal district of Santa Luzia, lying within the metropolitan region of Belo Horizonte in the Brazilian State of Minas Gerais. Sand flies were collected monthly in 2004-2005 using modified Falc?o light traps hung in the peridomiciles of houses and surrounding wooded areas in the district of Baronesa. A total of 1,552 sand flies belonging to seven species was collected, and an interesting pattern of the distribution of the most abundant species relative to the sampling locality was revealed. In the wooded areas Lutzomyia whitmani (Antunes & Coutinho) predominated, whereas in the urban area Lutzomyia longipalpis (Lutz & Neiva) was the most abundant species. These results indicate two possible epidemiological patterns of Leishmania transmission in Santa Luzia: one for American cutaneous leishmaniasis associated predominantly with wooded areas, and another for AVL, with transmission principally occurring around human habitations.