Variation in the prevalence and abundance of acanthocephalans in brown-nosed coatis Nasua nasua and crab-eating foxes Cerdocyon thous in the Brazilian Pantanal / Variação na prevalência e na abundância do parasitismo de acantócefalos em dois carnívoros silvestres do Pantanal brasileiro

Abstract Host infection by parasites is influenced by an array of factors, including host and environmental features. We investigated the relationship between host sex, body size and age, as well as seasonality on infection patterns by acanthocephalan in coatis (Procyonidae: Nasua nasua) and in crab-eating foxes (Canidae: Cerdocyon thous ) from the Brazilian Pantanal wetlands. Between 2006 and 2009, we collected faecal samples from these hosts and analyzed for the presence of acanthocephalan eggs. Prevalence, abundance and intensity of eggs of acanthocephalans were calculated. Egg abundance was analyzed using generalized linear models (GLM) with a negative binomial distribution and models were compared by Akaike criteria to verify the effect of biotic and abiotic factors. Prevalence of acanthocephalans was higher in the wet season in both host species but did not differ between host sexes; however, adult crab-eating foxes showed higher prevalence of acanthocephalan eggs than juveniles. In contrast, prevalence of acanthocephalan eggs found in coatis was higher in coati juveniles than in adults. Host age, season and maximum temperature were the top predictors of abundance of acanthocephalan eggs in crab-eating foxes whereas season and host sex were predictors of egg abundance in coatis. The importance of seasonality for abundance of acanthocephalan was clear for both host species. The influence of host-related attributes, however, varied by host species, with host gender and host age being important factors associated with prevalence and parasite loads.

Resumo A infecção de hospedeiro por parasitos é influenciada por uma série de fatores, incluindo características do hospedeiro e ambientais. Nós investigamos a relação entre sexo do hospedeiro, tamanho corporal e idade, bem como sazonalidade nos padrões de infecção por acantocéfalos em coatis (Procyonidae: Nasua nasua) e em cachorro-do-mato (Canidae: Cerdocyon thous ) do Pantanal brasileiro e quais fatores explicaram melhor a prevalência e a intensidade desses parasitos. Entre 2006 e 2009, coletamos amostras fecais desses hospedeiros e analisamos a presença de ovos de acantocéfalos. Prevalência, abundância e intensidade de ovos de acantócefálios foram calculados. A abundância de ovos foi analisada utilizando modelos lineares generalizados (GLM) com distribuição binomial negativa e os modelos foram comparados pelo critério de Akaike para verificar o efeito de fatores bióticos e abióticos. A prevalência de acantocéfalos foi maior na estação úmida em ambas as espécies de hospedeiros, mas não diferiu entre os sexos do hospedeiro; no entanto, os cachorros-do-mato adultos apresentaram maior prevalência de ovos de acantocéfalos do que em juvenis. Em contraste, a prevalência de ovos de acantocéfalos encontrados em coatis foi maior em juvenis do que em adultos. A idade do hospedeiro, a estação e a temperatura máxima foram os preditores de abundância de ovos de acantocéfalos em cachorro-do-mato, enquanto a estação e o sexo do hospedeiro foram preditores da abundância dos ovos do parasito em coatis. A importância da sazonalidade para a abundância do acantocéfalo foi clara para ambas as espécies hospedeiras. A influência dos atributos relacionados ao hospedeiro, no entanto, variou entre as espécies de hospedeiros, sendo o sexo e idade do hospedeiro fatores importantes associados à prevalência e às cargas parasitárias.

Genetic diversity of Hepatozoon spp. in rodents from Brazil.

Hepatozoon spp. are Apicomplexan protozoa that parasitize a wide diversity of vertebrate hosts. In Brazil, few studies have reported the occurrence of Hepatozoon spp. in rodent species. Additionally, an evaluation of the population structure and distribution of Hepatozoon species over several Brazilian biomes has not yet been performed. The present work aimed to investigate the genetic diversity of Hepatozoon spp. in rodents from 31 genera sampled in five Brazilian biomes. Samples were submitted to PCR assays for Hepatozoon spp. targeting two regions of the 18S rRNA gene. Infection by Hepatozoon spp. was detected in 195 (42.2%) rodents comprising 24 genera. Phylogenetic analyses of 18S rRNA sequences grouped all sequences in the clade of Hepatozoon spp. previously detected in rodents and reptiles, apart from those detected in domestic/wild carnivores. These data raise two non-exclusive hypotheses: (i) rodents play an important role as intermediate or paratenic hosts for Hepatozoon infections in reptiles; and (ii) rodents do not seem to participate in the epidemiology of Hepatozoon infections of domestic/wild canids and felids in Brazil. TCS analyses performed with available 18S rRNA Hepatozoon sequences detected in rodents from Brazil showed the occurrence of six haplotypes, which were distributed in two large groups: one from rodents inhabiting the coastal region of Brazil and Mato Grosso state, and another from rodents from the central region of the country. A wide survey of the South American territory will help to elucidate the evolutionary history of Hepatozoon spp. parasitizing Rodentia in the American continent.

Variation in the prevalence and abundance of acanthocephalans in brown-nosed coatis Nasua nasua and crab-eating foxes Cerdocyon thous in the Brazilian Pantanal.

Host infection by parasites is influenced by an array of factors, including host and environmental features. We investigated the relationship between host sex, body size and age, as well as seasonality on infection patterns by acanthocephalan in coatis (Procyonidae: Nasua nasua) and in crab-eating foxes (Canidae: Cerdocyon thous ) from the Brazilian Pantanal wetlands. Between 2006 and 2009, we collected faecal samples from these hosts and analyzed for the presence of acanthocephalan eggs. Prevalence, abundance and intensity of eggs of acanthocephalans were calculated. Egg abundance was analyzed using generalized linear models (GLM) with a negative binomial distribution and models were compared by Akaike criteria to verify the effect of biotic and abiotic factors. Prevalence of acanthocephalans was higher in the wet season in both host species but did not differ between host sexes; however, adult crab-eating foxes showed higher prevalence of acanthocephalan eggs than juveniles. In contrast, prevalence of acanthocephalan eggs found in coatis was higher in coati juveniles than in adults. Host age, season and maximum temperature were the top predictors of abundance of acanthocephalan eggs in crab-eating foxes whereas season and host sex were predictors of egg abundance in coatis. The importance of seasonality for abundance of acanthocephalan was clear for both host species. The influence of host-related attributes, however, varied by host species, with host gender and host age being important factors associated with prevalence and parasite loads.

Hantavirus pulmonary syndrome and rodent reservoirs in the savanna-like biome of Brazil's southeastern region.

This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome.

The strategies to reduce iron deficiency in blood donors randomized trial: design, enrolment and early retention.

BACKGROUND AND OBJECTIVES: Repeated blood donation produces iron deficiency. Changes in dietary iron intake do not prevent donation-induced iron deficiency. Prolonging the interdonation interval or using oral iron supplements can mitigate donation-induced iron deficiency. The most effective operational methods for reducing iron deficiency in donors are unknown. MATERIALS AND METHODS: 'Strategies To Reduce Iron Deficiency' (STRIDE) was a two-year, randomized, placebo-controlled study in blood donors. 692 donors were randomized into one of two educational groups or one of three interventional groups. Donors randomized to educational groups either received letters thanking them for donating, or, suggesting iron supplements or delayed donation if they had low ferritin. Donors randomized to interventional groups either received placebo, 19-mg or 38-mg iron pills. RESULTS: Iron deficient erythropoiesis was present in 52·7% of males and 74·6% of females at enrolment. Adverse events within 60 days of enrolment were primarily mild gastrointestinal symptoms (64%). The incidence of de-enrolment within 60 days was more common in the interventional groups than in the educational groups (P = 0·002), but not more common in those receiving iron than placebo (P = 0·68). CONCLUSION: The prevalence of iron deficient erythropoiesis in donors enrolled in the STRIDE study is comparable to previously described cohorts of regular blood donors. De-enrolment within 60 days was higher for donors receiving tablets, although no more common in donors receiving iron than placebo.

A 5-year analysis of the helicopter air mercy service in Richards Bay, South Africa.

BACKGROUND: A helicopter emergency medical service (HEMS) was established in 2005 in Richards Bay, KwaZulu-Natal, South Africa, to provide primary response and inter-facility transfers to a largely rural area with a population of 3.4 million people. OBJECTIVE: To describe the first 5 years of operation of the HEMS. METHODS: A chart review of all flights from 1 January 2006 to 31 December 2010 was conducted. RESULTS: A total of 1 429 flights were undertaken; 3 were excluded from analysis (missing folders). Most flights (88.4%) were inter-facility transfers (IFTs). Almost 10% were cancelled after takeoff. The breakdown by age was 61.9% adult, 15.1% paediatric and 21.6% neonate. The main indications for IFTs were obstetrics (34.5%), paediatrics (27.9%) and trauma (15.9%). For primary response most cases were trauma (72.9%) and obstetrics (11.3%). The median on-scene time for neonates was significantly longer (48 min, interquartile range (IQR) 35 - 64 min) than that for adults (36 min, IQR 26 - 48; p < 0.001) and paediatrics (36 min, IQR 25 - 51; p < 0.02). On-scene times for doctor-paramedic crews (45 min, IQR 27 - 50) were significantly longer than for paramedic-only crews (38 min, IQR 27 - 57; p < 0.001). CONCLUSION: The low flight-to-population ratio and primary response rate may indicate under-utilisation of the air medical service in an area with a shortage of advanced life support crews and long transport distances. Further studies on HEMSs in rural Africa are needed, particularly with regard to cost-benefit analyses, optimal activation criteria and triage systems.

Prevalence of myopia in a population with malocclusions.

AIM: The purpose of this study was to investigate the prevalence of myopia among a paediatric population with malocclusions. MATERIALS AND METHODS: A total of 322 consecutive patients of the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, were enlisted for the study and 292 were selected according to the exclusion criteria. Pretreatment diagnostic data, which included radiographic cephalometric and dental cast evaluation, were recorded and presence of myopia was assessed through an ophthalmological examination. Differences in the prevalence of myopia by sex and malocclusion were analysed by using Pearson's chi-square and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (N=162), Class II division 1 (N=75), Class II division 2 (N=38), or Class III (N=12). No gender influence was found for myopia or malocclusion. No differences were recorded when analysing the influence of sex on the prevalence of myopia in classes of malocclusion. A statistical significant higher prevalence was found for subjects showing myopia in Class II division 1 malocclusion, while no other significant differences were found for prevalence in the other classes of malocclusions. DISCUSSION: Few studies investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature. A higher prevalence of myopia was found in patients with Class II division 1: as expected no other significant association was found. CONCLUSION: The findings of the present study suggest a possible association between myopia and Class II, but further studies are needed to confirm and explain this observation.

Prevalence of hyperopia and strabismus in a paediatric population with malocclusions.

AIM: The purpose of this study was to investigate the prevalence of hyperopia and strabismus among a paediatric population with malocclusions. MATERIALS AND METHODS: From a total of 322 consecutive patients observed at the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, 176 were selected for the study according to the exclusion criteria. Pretreatment diagnostic data, which included radiographic, cephalometric and dental cast evaluation, were recorded and presence of hyperopia or strabismus was assessed through an ophthalmological examination. Differences in incidence rates of strabismus or hyperopia by sex and malocclusion were analysed by using the chi-square (Pearson's chi-square test) and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (122), Class II division 1 (26), Class II Division 2 (9), or Class III (19); after ophthalmological examination, hyperopia was detected in 8.6% of patients, while strabismus was present in 3.6% of them. No gender influence was found for hyperopia, strabismus or malocclusion. DISCUSSION: Few studies investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature; the present study did not highlight differences in the prevalence of hyperopia or strabismus in the three Angle classes malocclusion. CONCLUSION: The findings of the present study did not suggest a possible association between hyperopia or strabismus and sagittal malocclusion, but future studies are needed to confirm and explain this observation.

Human and animal infections by vaccinia-like viruses in the state of Rio de Janeiro: a novel expanding zoonosis.

Since 1999, vesicular infections caused by Orthopoxvirus in humans and animals, mainly in dairy cattle, have been identified in 20 municipalities in the Rio de Janeiro state of Brazil. This paper describes studies conducted in counties of the northwestern, middle-Paraíba Valley and southern regions of the Rio de Janeiro state where 77 human, 346 bovine and 78 rodent samples were collected over the past ten years. Laboratory investigations using virus isolation, electron microscopy, molecular biology (PCR) and serological analysis confirmed Orthopoxvirus infections in 77.9% of human, 49.2% of dairy cattle and 17.9% of rodent samples. The characterisation of the Cantagalo/IOC strain reconfirmed that this virus was a vaccinia-like virus. In other regions of the Rio de Janeiro state, vesicular/pustular infections in animals and humans are suspected but these have not yet been confirmed. A continuous surveillance system has been established to monitor these regions in addition to several other states of the Brazilian Federation.

Prevalence of astigmatism in a paediatric population with malocclusions.

AIM: The purpose of this study was to investigate the prevalence of astigmatism among a paediatric population. MATERIALS AND METHODS: A total of 322 consecutive patients of the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, were enlisted for the study and 176 were selected according to the exclusion criteria. Pre- treatment diagnostic data, which included radiographic cephalometric and dental cast evaluation, were recorded and presence of astigmatism was assessed through an ophthalmological examination. Differences in the prevalence of astigmatism by sex and malocclusion were analysed by using the chi-square (Pearson's chi-square test) and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (N=122), Class II Division 1 (N=26), Class II Division 2 (N=9), or Class III (N=19); according to the transverse malocclusion patients were classified into cross-bite (N=39) and no cross-bite (N=137) groups; after ophthalmological examination astigmatism was detected in 32 patients (18.18%). Statistically significant correlations were found between astigmatism and cross-bite (p < 0.0001), while no associations were found with other malocclusions. No gender influence was found for astigmatism or malocclusion. DISCUSSION: Few study investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature. A higher prevalence of astigmatism was found in patients with cross-bite: as expected no other significant association was found. The relationship between astigmatism and cross-bite could be either related to a specific skeletal pattern, which could induce visual alterations, or to the effect of abnormal visual input on the postural system, which could induce stomatognathic alterations. CONCLUSION: The findings of the present study suggest a possible association between astigmatism and cross-bite, but future studies are needed to confirm and explain this observation.

Rehabilitative treatment in peripheral artery disease: protocol application and follow-up.

AIM: Peripheral arterial disease (PAD) is a chronic figure suitable to be treated at the II stage to prevent the extreme developments both of the critical limb ischemia and the amputation, as well. The aim of this study was to establish a rehabilitation program (pharmacological and physical) focused not only on the improvement of the flow but also on the metabolic rebalancing in the claudicant limb. METHODS: The study enrolled 222 patients, (125 non-diabetics and 97 diabetics): 54 II A and 168 II B stage; 172 patients (131 II B and 41 II A; 104 non-diabetics and 68 diabetics) were submitted to iv. L-propionil carnytine (Lpc) and physical training on treadmill or exercise bike and 50 patients to iv. therapy alone. Instrumental (Rheoscreen, Oximetry, ABI, walking distance measurement) and clinical checks (questionnaire - Appendix 1) were performed at days: T0, T45,T 90,T180, T230 and during the follow up stated at T 90,T180,T360 from T 230 (end of DH). RESULTS: A significant increasing of the walking distance has been reached in the group undergoing the rehabilitation program. Treadmill: non-diabetics +261.48% at 0% and +122.53% at slope 10% (T230) further increasing to +502.31% at 0% and +289.42% at slope 10% (T360); diabetics: + 158.49% at T0 and + 98.26% at slope 10% (T230) further increased to +287.74% at 0% and +197.39% at 10% (T360) in comparison with the group which had only iv. Lpc : non-diabetics +141.63% at 0% and +104.08% at slope 10% (T230) further increased to +202.064% at 0% and +155.10% at slope 10% (T360); diabetics: +109.124% at T0 and +100% at slop 10% (T230) further increased to +171.08% at 0% and +140% at 10% (T360) . Exercise bike: non-diabetics: +170.27% at T230 in comparison T0 increased to +305.4% at T360; diabetics: +166.66 at T230 reaching +288.88% at T 360. CONCLUSION: Our rehabilitative program gives not only good results at the end of the treatment but mainly stable, with the chance to reach further improving of both walking distance and quality of life, particularly in those patients which observe constantly the physical training.

Variation in the helminth community structure of Thrichomys pachyurus (Rodentia: Echimyidae) in two sub-regions of the Brazilian Pantanal: the effects of land use and seasonality.

The Pantanal is a large ecosystem located in South America. This preserved area is seasonally flooded due to abundant rainfall during the summer and the subsequent overflow of the Paraguai River. In this paper, we examine the helminth community structure in the wild rodent Thrichomys pachyurus during the wet and dry seasons in two locations of the preserved and cattle ranching areas in the Southern Pantanal. We identified 12 species of helminth, and, although we did not find any differences in species richness between locations within the Pantanal, we found that richness was higher during the wet season. Helminth species were largely aggregated in both farm locations and during seasons. The most common helminth species were more abundant during the dry season than during the wet season, which may have been due to the increased habitat availability and rodent population increase. The intensity of the infection also followed the same pattern for most helminths. The trichostrongylids (Heligmostrongylus crucifer, H. almeidai and Pudica cercomysi) were dominant at both farm locations. The land use of each area was not correlated with helminth diversity. However, species composition of the helminth community of T. pachyurus differed between locations and may be correlated with environmental differences between the habitats. The seasonality of the Pantanal was highly correlated with helminth parasitism in T. pachyurus.

Genetic characterization of a Juquitiba-like viral lineage in Oligoryzomys nigripes in Rio de Janeiro, Brazil.

Hantaviruses, family Bunyaviridae, are rodent-borne RNA viruses that have caused cases of hantavirus cardiopulmonary syndrome (HCPS) in various regions of the Americas. There are five hantaviral lineages associated with HCPS in Brazil: Juquitiba virus (JUQV), Araraquara virus (ARAV), Laguna Negra-like virus (LNV), Castelo dos Sonhos virus (CASV), and Anajatuba virus (ANAJV). Three additional hantaviruses have been described in rodents alone: Rio Mearim virus, Jaborá virus, and a hantavirus lineage related to Seoul virus. This study describes the genetic detection and characterization of a Juquitiba-like hantavirus in Oligoryzomys nigripes, or the black-footed pygmy rice rat, in the Serra dos Orgãos National Park, Rio de Janeiro State, where so far no cases of HCPS have been reported.

What is the role of small rodents in the transmission cycle of Trypanosoma cruzi and Trypanosoma evansi (Kinetoplastida Trypanosomatidae)? A study case in the Brazilian Pantanal.

Determining the reservoir hosts for parasites is crucial for designing control measures, but it is often difficult to identify the role that each host species plays in maintaining the cycle of infection in the wild. One way to identify potential maintenance hosts is to estimate key parameters associated with transmission and pathogenicity. Here we assess the potential for three native rodent species of the Brazilian Pantanal (Clyomys laticeps, Thrichomys pachyurus and Oecomys mamorae) to act as reservoir or maintenance hosts of Trypanosoma evansi, an important parasite of domestic livestock. By analyzing blood parameters of naturally infected wild-caught rodents of these species, we compared their levels of parasitemia and anemia due to T. evansi infection with literature values for other host species infected by this parasite. We also analyzed levels of these blood parameters relative to infection by Trypanosoma cruzi, the causative agent of Chagas disease in humans, for which wild rodents are already thought to be important reservoir species. All three species showed low impacts of the two trypanosomes on their blood parameters compared to other species, suggesting that they experience a low virulence of trypanosome infection under natural conditions in the Pantanal and might act as maintenance hosts of trypanosome infections. The low parasitemia of trypanosome infections suggests that these rodents play a secondary role in the transmission cycle compared to other species, especially compared to the capybara (Hydrochaeris hydrochaeris) which also experiences low pathogenicity due to infection despite much higher levels of parasitemia.

Guia dos roedores do Brasil, com chaves para gêneros baseadas em caracteres externos

[Prólogo] A concepção da idéia da elaboração deste guia surgiu durante a realização do I Curso de Taxonomia e Sistemática de Roedores Silvestres, realizado no Centro de Pesquisa Aggeu Magalhães, na Fiocruz, em Recife, em 2005, para técnicos de serviços de saúde que atuavam no grupo de vigilância ecoepidemiológica de hantavírus da Secretaria de Vigilância em Saúde (SVS), do Ministério da Saúde (MS). Durante esse curso, ficou evidente a necessidade de um guia para identificação dos roedores brasileiros considerando-se a necessidade de uma identificação inicial pelos técnicos envolvidos nas atividades de pesquisa de campo e no monitoramento e/ou controle de roedores reservatórios em áreas endêmicas de zoonoses.

Effects of endogenous cyclotronic ionic resonance (ICR) on macular diabetic edema: preliminary results.

The intent in this research was to verify the effects of the application of low frequency magnetic fields to cases of macular diabetic edema. We treated six patients afflicted by non-proliferating diabetic retinopathy with macular oedema. Quantitative clinical appraisals of the retinal thickness were obtained for the Optical Coherence Tomography (OCT I). None of the cases affected by non-cystoid macular oedema (non-CMO), or with a relevant ischemic component, evidenced by retinal fluorangiography, had further worsening in their clinical course during the treatment. Only one of the patients, who underwent a long treatment period with ICR demonstrated a significant reduction of the macular edema, with no need of other invasive therapeutic procedures (intravitreous injection of triamcinolone and/or laser therapy).

Effects of habitat fragmentation on wild mammal infection by Trypanosoma cruzi.

Expansion of human activities frequently results in habitat fragmentation, a phenomenon that has been widely recognized in the last decades as one of the major threats to world's biodiversity. The transformation of a continuous forest into a fragmented area results in a hyper-dynamic landscape with unpredictable consequences to overall ecosystem health. The effect of the fragmentation process on Trypanosoma cruzi infection among small wild mammals was studied in an Atlantic Rain Forest landscape. Comparing continous forest to fragmented habitat, marsupials were less abundant than rodents in the continuous landscape. An overall decrease in small wild mammal richness was observed in the smaller fragments. An anti-T. cruzi seroprevalence of 18% (82/440) was deteced by immunofluorescence assay. Moreover, this seroprevalence was higher in the fragmented habitat than in the continuous forest. According to the collected data, 3 main factors seem to modulate infection by T. cruzi in small wild mammals: (i) habitat fragmentation; (ii) biodiversity loss; (iii) increase of marsupial abundance in mammal communities. Furthermore, an extremely mild controlled infection by T. cruzi was detected since no patent parasitaemia could be detected in fresh blood samples, and no parasites were isolated by haemoculture.

Small mammal populations of an agroecosystem in the Atlantic Forest domain, southeastern Brazil.

This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133), Akodon cursor (n = 74), Oligoryzomys nigripes (n = 25) and the marsupials Didelphis aurita (n = 58) and Philander frenatus (n = 50). Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry) months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.

Variables that modulate the spatial distribution of Trypanosoma cruzi and Trypanosoma evansi in the Brazilian Pantanal.

An evaluation was made on how the landscape and cattle ranching affect the transmission cycles and the patterns of tripanosomatid infection (Trypanosoma cruzi and Trypanosoma evansi) of small wild mammals in the Pantanal. This region comprises a large natural environment with a multiplicity of habitats, wide variety of biodiversity besides the presence of livestock. T. cruzi and T. evansi infections were evaluated by parasitological and serological methods in one preserved and one cattle ranching area. The diversity of the small mammal fauna showed to be the same in the two studied areas, however, their relative abundance was different. Distinct enzootiological scenarios of both trypanosomatids could be observed. Transmission of T. cruzi occurred mainly in forested areas, in the two study areas, while T. evansi occurred dispersed among all habitats studied in the unpreserved area. The arboreal rodent Oecomys mamorae, the most abundant species in both areas, displayed high T. cruzi and T. evansi serum prevalence and parasitemias. Also, the caviomorph rodent Thrichomys pachyurus was shown to be an important host due to its expressive relative abundance, prevalence of infection by both trypanosomatid species and a broad range use of habitats. The role of the small mammal fauna in the transmission cycle of both trypanosomes species seems to be distinct according to land use since we found a broad range of T. evansi infected hosts in the preserved area in contrast to cattle ranching area and a half number of the rodents species infected with T. cruzi in unpreserved in comparison to protect area. The present study showed that cattle ranching in this study area did not enhance overall prevalence of T. cruzi infection among small wild mammals. Together with the observation that small mammals diversity in FA is similar to RN area suggest that ranching activity may also not necessarily conduct to biodiversity loss or risk of Chagas disease.

Mapping of the distribution of Trypanosoma cruzi infection among small wild mammals in a conservation unit and its surroundings (Northeast-Brazil).

Maps are a useful tool that permits correlation of landscapes with hotspots of parasite transmission. Here, they were used as a tool for geovisualization to evaluate variables involved in the transmission of Trypanosoma cruzi among small wild mammals in an area endemic for Chagas disease, the "Serra da Capivara" National Park (PARNA) and its surroundings in Piauí State, Northeast Brazil. The implementation of a Geographical Information System (GIS) allowed the observation that a previously noted aggregated distribution of Triatoma sordida and Triatoma brasiliensis, T. cruzi prevalence and infection pattern of small wild mammals was directly or indirectly influenced by the local relief and human action. Small mammalian species diversity was higher in mesic refugia inside the park and in its buffer zone and lower in the disturbed area by anthropic activities. Didelphis albiventris was more abundant in the areas affected by human action. Thrichomys laurentius demonstrated to be an eclectic species and a competent reservoir of T. cruzi, being infected in all study areas. Small wild mammals infected with the TCII genotype of T. cruzi were localized only in the buffer zone of PARNA while TCI infected specimens were found in both areas, inside the PARNA and its buffer zone. The impact of biodiversity loss on the transmission cycle of T. cruzi in the wild environment was discussed.