Phlebotomine sand flies (Diptera: Psychodidae) associated with changing patterns in the transmission of the human cutaneous leishmaniasis in French Guiana

Between March 2000 and December 2001 a survey of the sand flies (Diptera: Phlebotominae) of French Guiana was carried out during 14 nights of captures with CDC light-traps and Malaise traps, and resulted in the collection of 2245 individuals of 38 species. The most abundant species were Lutzomyia (Trichophoromyia) ininii Floch & Abonnenc, Lu.(Psychodopygus) squamiventris maripaensis Floch & Abonnenc, and Lu .(Nyssomyia) flaviscutellata Mangabeira. Half of the collected sand flies females were dissected under field conditions and five species were found harboring Leishmania-like parasites. The Leishmania (Kinetoplastidae: Trypanosomatidae) species were identified by molecular typing, and for the first time Lu. (Nys.) flaviscutellata was found harboring Leishmania (Viannia) guyanensis and Lu. (Tri) ininii harboring unknown Leishmania. The first record for French Guiana of Lu. (Psy.) squamiventris maripaensis harboring L. (V.) naiffi, was also reported. The patterns of diversification of the human cutaneous leishmaniasis transmission in French Guiana are discussed.

Circulation of Campylobacter spp. in rhesus monkeys (Macaca mulatta) held in captivity: a longitudinal study

Campylobacteriosis is an extremely important zoonosis, circulating freely in the environment. In nonhuman primates kept in open facilities and bred for experimental purposes, the presence of Campylobacter spp. could cause severe damage to the production and interfere with the results of scientific research. In this paper, we assessed the circulation of Campylobacter spp. in a colony of clinically healthy rhesus monkeys (Macaca mulatta) destined to research. The analysis was carried out during seven non-consecutive years. Data showed that despite several changes made in animal management along the studied years in order to control this zoonosis, reduction of bacterial charge did not occur. Significant differences among the age groups and sex were observed. Infants showed higher susceptibility than adult animals. In general males were more infected than females. Modifications adopted in the handling techniques need to be reviewed with the intent of improving the production, reducing bacterial infection of the stock and avoiding undesirable cross reactions in the research carried out with these animals. Therefore, this paper alerts professionals that work directly with captive rhesus monkeys about the risks of Campylobacter spp. infection and possible interference on the experimental procedures.

Patterns of co-association of C-reactive protein and nitric oxide in malaria in endemic areas of Iran

In addition to numerous immune factors, C-reactive protein (CRP) and nitric oxide (NO) are believed to be molecules of malaria immunopathology. The objective of this study was to detect CRP and NO inductions by agglutination latex test and Griess microassay respectively in both control and malaria groups from endemic areas of Iran, including Southeastern (SE) (Sistan & Balouchestan, Hormozgan, Kerman) and Northwestern (NW) provinces (Ardabil). The results indicated that CRP and NO are produced in all malaria endemic areas of Iran. In addition, more CRP and NO positive cases were observed amongst malaria patients in comparison with those in control group. A variable co-association of CRP/NO production were detected between control and malaria groups, which depended upon the malaria endemic areas and the type of plasmodia infection. The percentage of CRP/NO positive cases was observed to be lower in NW compare to SE region, which may be due to the different type of plasmodium in the NW (Plasmodium vivax) with SE area (P. vivax, Plasmodium falciparum, mixed infection). The fluctuations in CRP/NO induction may be consistent with genetic background of patients. Although, CRP/NO may play important role in malaria, their actual function and interaction in clinical forms of disease remains unclear.

Evidence for the co-circulation of dengue virus type 3 genotypes III and V in the Northern region of Brazil during the 2002-2004 epidemics

The reintroduction of dengue virus type 3 (DENV-3) in Brazil in 2000 and its subsequent spread throughout the country was associated with genotype III viruses, the only DENV-3 genotype isolated in Brazil prior to 2002. We report here the co-circulation of two different DENV-3 genotypes in patients living in the Northern region of Brazil during the 2002-2004 epidemics. Complete genomic sequences of viral RNA were determined from these epidemics, and viruses belonging to genotypes V (Southeast Asia/South Pacific) and III were identified. This recent co-circulation of different DENV-3 genotypes in South America may have implications for pathological and epidemiological dynamics.

Phlebotominae (Diptera: Psycodidae) fauna in the Chaco region and Cutaneous Leishmaniasis transmission patterns in Argentina

In Argentina, the incidence of American Cutaneous Leishmaniasis (ACL) has shown a steady increase over the last few decades. In the Chaco biogeographical region, specifically, several outbreaks of ACL were recently reported in addition to the usual time-space scattering of ACL cases. However, little is known about the sandfly composition in the eastern, humid Chaco (HC) region or the western, dry Chaco (DC) region. Therefore, phlebotomine captures were performed throughout this region and an analysis of the distribution of reported ACL cases was conducted in order to assess the vector diversity in ACL endemic and epidemic scenarios in the Chaco region. The results support the hypothesis of two distinct patterns: (1) the DC, where Lutzomyia migonei was the most prevalent species, had isolated ACL cases and a zoonotic cycle; (2) the HC, where Lutzomyia neivai was the most prevalent species, had an increase in ACL incidence and outbreaks and an anthropozoonotic cycle. The epidemic risk in the Chaco region may be associated with the current climate trends, landscape modification, connection with other ACL foci, and Lu. neivai predominance and abundance. Therefore, changes in sandfly population diversity and density in the Chaco region are an indicator of emergent epidemic risk in sentinel capture sites.

Life cycle, feeding and defecation patterns of Rhodnius ecuadoriensis (Lent & León 1958) (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

Rhodnius ecuadoriensis is the second most important vector of Chagas Disease (CD) in Ecuador. The objective of this study was to describe (and compare) the life cycle, the feeding and defecation patterns under laboratory conditions of two populations of this specie [from the provinces of Manabí (Coastal region) and Loja (Andean region)]. Egg-to-adult (n = 57) development took an average of 189.9 ± 20 (Manabí) and 181.3 ± 6.4 days (Loja). Mortality rates were high among Lojan nymphs. Pre-feeding time (from contact with host to feeding initiation) ranged from 4 min 42 s [nymph I (NI)] to 8 min 30 s (male); feeding time ranged from 14 min 45 s (NI)-28 min 25 s (male) (Manabí) and from 15 min 25 s (NI)-28 min 57 s (nymph V) (Loja). The amount of blood ingested increased significantly with instar and was larger for Manabí specimens (p < 0.001). Defecation while feeding was observed in Manabí specimens from stage nymph III and in Lojan bugs from stage nymph IV. There was a gradual, age-related increase in the frequency of this behaviour in both populations. Our results suggest that R. ecuadoriensis has the bionomic traits of an efficient vector of Trypanosoma cruzi. Together with previous data on the capacity of this species to infest rural households, these results indicate that control of synanthropic R. ecuadoriensis populations in the coastal and Andean regions may have a significant impact for CD control in Ecuador and Northern Peru.

The circulation of human astrovirus genotypes in the Central West Region of Brazil

Out of 1,588 faecal samples of children taken from three locations of the Central West Region of Brazil, 57 were positive for astroviruses (HAstVs) using reverse transcription-polymerase chain reaction (RT-PCR). They were genotyped by nested RT-PCR and/or genomic sequencing. HAstV-1 (42.8%), HAstV-2 (23.2%), HAstV-3 (3.6%), HAstV-4 (14.3%) and HAstVs -5, -6, -7 and -8 (1.8% each) were detected. In Goiânia and Campo Grande, HAstV-1 was the most frequently detected genotype while in Brasília (DF) it was HAstV-2. Shifts in the circulation of astrovirus genotypes were observed in DF and Campo Grande. All samples collected by rectal swabs were viral negative. The astrovirus genotypes were detected in all age groups and there was no correlation between genotype and age group.

Influence of blood meal and mating in reproduction patterns of Triatoma brasiliensis females (Hemiptera: Reduviidae) under laboratory conditions

The influence of blood meal and mating on Triatoma brasiliensis (Neiva) female fecundity, fertility, life-span and the preoviposition period were investigated under laboratory conditions. Nourishment increased fecundity, fertility and adult lifespan, whereas mating increased fecundity, fertility and decreased the preoviposition period. Females also required more than one mating to reach their full reproductive potential. Results indicate that both nourishment and mating are important in T. brasiliensis proliferation. Such information will help towards developing effective control strategies of this vector of Chagas disease.

Life cycle of Triatoma ryckmani (Hemiptera: Reduviidae) in the laboratory, feeding patterns in nature and experimental infection with Trypanosoma cruzi

A cohort initiated with 121 eggs, yielding 105 first instar nymphs (eclosion rate: 86.78%), allowed us to observe the entire life cycle of Triatoma ryckmani under laboratory conditions (24ºC and 62% relative humidity), by feeding them on anesthetized hamsters. It was possible to obtain 62 adults and the cycle from egg to adult took a mean of 359.69 days with a range of 176-529 days (mortality rate of nymphs: 40.95%). Mean life span of adults was of 81 days for females and 148 days for males. The developmental periods of 4th and 5th nymphs were longer than those of the other instars. This suggests that young siblings have a better chance of taking a hemolymph meal from older ones, in order to survive during fasting periods during prolonged absences of vertebrate hosts from natural ecotopes. The stomach contents of 37 insects showed blood from rodents (15 cases), lizards (7 cases), birds (6 cases) and insect hemolymph (7 cases). Out of 10 insects fed by xenodiagnosis on a Trypanosoma cruzi infected mouse, all but one became infected with the parasite.

Omental and pleural milky spots: different reactivity patterns in mice infected with Schistosoma mansoni reveals coelomic compartmentalisation

In vertebrate animals, pleural and peritoneal cavities are repositories of milky spots (MS), which constitute an organised coelom-associated lymphomyeloid tissue that is intensively activated by Schistosoma mansoni infection. This study compared the reactive patterns of peritoneal MS to pleural MS and concluded from histological analysis that they represent independent responsive compartments. Whole omentum, lungs and the entire mediastinum of 54 S. mansoni-infected mice were studied morphologically. The omental MS of infected animals were highly activated, modulating from myeloid-lymphocytic (60 days of infection) to lymphomyeloid (90 days of infection) and lymphocytic or lymphoplasmacytic (160 days of infection) types. The non-lymphoid component predominated in the acute phase of infection and was expressed by monocytopoietic, eosinopoietic and neutropoietic foci, with isolated megakaryocytes and small foci of late normoblasts and mast cells. Nevertheless, pleural or thoracic MS of infected mice were monotonous, consisting of small and medium lymphocytes with few mast and plasma cells and no myeloid component. Our data indicate that compartmentalisation of the MS response is dependent on the lymphatic vascularisation of each coelomic cavity, limiting the effects or consequences of any stimulating or aggressive agents, as is the case with S. mansoni infection.

Schistosoma mansoni: magnetic resonance analysis of liver fibrosis according to WHO patterns for ultrasound assessment of schistosomiasis-related morbidity

For the last two decades, ultrasound (US) has been considered a surrogate for the gold standard in the evaluation of liver fibrosis in schistosomiasis. The use of magnetic resonance imaging (MRI) is not yet standardised for diagnosing and grading liver schistosomal fibrosis. The aim of this paper was to analyse MRI using an adaptation of World Health Organization (WHO) patterns for US assessment of schistosomiasis-related morbidity. US and MRI were independently performed in 60 patients (42.1 ± 13.4 years old), including 37 men and 23 women with schistosomiasis. Liver involvement appraised by US and MRI was classified according to the WHO protocol from patterns A-F. Agreement between image methods was evaluated by kappa index (k). The correlation between US and MRI was poor using WHO patterns [k = 0.14; confidence interval (CI) 0.02; 0.26]. Even after grouping image patterns as "A-D", "Dc-E" and "Ec-F", the correlation between US and MRI remained weak (k = 0.39; CI 0.21; 0.58). The magnetic resonance adaptation used in our study did not confirm US classification of WHO patterns for liver fibrosis.

Serum hyaluronan and collagen IV as non-invasive markers of liver fibrosis in patients from an endemic area for schistosomiasis mansoni: a field-based study in Brazil

Non-invasive markers of fibrosis have been used to diagnose liver fibrosis in a variety of diseases. Hyaluronic acid (HA) and collagen IV (C-IV) levels were measured in the sera of patients from an endemic area for schistosomiasis in Brazil to diagnose and to rank the intensity of liver fibrosis. Seventy-nine adult patients with schistosomiasis, in the age range of 21-82 years (49 ± 13.4) were submitted to clinical and ultrasonographic examinations. Ultrasound was employed to diagnose and categorise liver fibrosis according to World Health Organization patterns. Serum HA and C-IV levels were measured using commercial ELISA kits. Ultrasound revealed six patients with intense liver fibrosis, 21 with moderate, 23 with light and 29 without. Serum HA was able to separate individuals with fibrosis from those without (p < 0.001) and light from intense fibrosis (p = 0.029), but C-IV was not (p = 0.692). The HA diagnostic accuracy for fibrosis was 0.89. The 115.4 ng/mL cut-off level diagnosed patients with fibrosis (sensitivity 0.98, specificity 0.64). HA correlated positively with portal hypertension. Periportal fibrosis (subjective evaluation), age and collateral circulation predicted HA increase. In conclusion, we propose that serum HA can be used to identify patients with liver fibrosis in an endemic area for schistosomiasis mansoni in Brazil.

Circulation of hantaviruses in the influence area of the Cuiabá-Santarém Highway

We describe evidence of circulation of hantaviruses in the influence area of the Santarém-Cuiabá Highway (BR-163) in the Brazilian Amazon through the prevalence of specific antibodies against hantaviruses in inhabitants living in four municipalities of this area: Novo Progresso (2.16%) and Trairão (4.37%), in state of Pará (PA), and Gua-rantã do Norte (4.74%) and Marcelândia (9.43%), in state of Mato Grosso. We also demonstrate the ongoing association between Castelo dos Sonhos virus (CASV) and hantavirus pulmonary syndrome (HPS) cases in the Castelo dos Sonhos district (municipality of Altamira, PA) and the first report of CASV in the municipalities of Novo Progresso and Guarantã do Norte. The results of this work highlight the risk for a possible increase in the number of HPS cases and the emergence of new hantavirus lineages associated with deforestation in this Amazonian area after the conclusion of paving works on BR-163 Highway.

Serologic evidence of the recent circulation of Saint Louis encephalitis virus and high prevalence of equine encephalitis viruses in horses in the Nhecolândia sub-region in South Pantanal, Central-West Brazil

As in humans, sub-clinical infection by arboviruses in domestic animals is common; however, its detection only occurs during epizootics and the silent circulation of some arboviruses may remain undetected. The objective of the present paper was to assess the current circulation of arboviruses in the Nhecolândia sub-region of South Pantanal, Brazil. Sera from a total of 135 horses, of which 75 were immunized with bivalent vaccine composed of inactive Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus(WEEV) and 60 were unvaccinated, were submitted to thorough viral isolation, reverse transcriptase polymerase chain reaction (RT-PCR) and neutralization tests for Saint Louis encephalitis virus (SLEV), EEEV, WEEV and Mayaro virus (MAYV). No virus was isolated and viral nucleic-acid detection by RT-PCR was also negative. Nevertheless, the prevalence of neutralizing antibodies in horses older than seven months was 43.7% for SLEV in equines regardless of vaccine status, and 36.4% for WEEV and 47.7% for EEEV in unvaccinated horses. There was no evidence of MAYV infections. The serologic evidence of circulation of arboviruses responsible for equine and human encephalitis, without recent official reports of clinical infections in the area, suggests that the Nhecolândia sub-region in South Pantanal is an important area for detection of silent activity of arboviruses in Brazil.

Developmental and reproductive patterns of Triatoma brasiliensis infected with Trypanosoma cruzi under laboratory conditions

The aim of this work was to study the interaction between Trypanosoma cruzi-1 and Triatoma brasiliensis. A group of 1st instar nymphs was initially fed on T. cruzi-infected mice and a control group was fed on uninfected mice. From the second feeding onwards, both groups were otherwise fed on non-infected mice. The resulting adults were grouped in pairs: infected male/uninfected female, uninfected male/infected female, infected male and female and uninfected male/uninfected female. The infection affected only the 1st instar nymphs, which took significantly more time to reach the 2nd instar than uninfected nymphs. The differences in the molting time between the infected and uninfected nymphs from the 2nd to the 5th instars were not statistically significant. Both groups presented similar rates of nymphal mortality and reproductive performance was not significantly affected by infection in any of the treatments.