Species Diversity and Flagellate Infections in the Sand Fly Fauna near Porto Grande, State of Amapá, Brazil (Diptera: Psychodidae. Kinetoplastida: Trypanosomatidae)

Forty-six species of Lutzomyia and one species of Brumptomyia were identified among 20,008 sand flies collected in central Amapá. L. squamiventris maripaensis, L. infraspinosa, L. umbratilis and L. ubiquitalis accounted for 66% of the specimens caught in light traps, and L. umbratilis was the commonest of the 16 species found on tree bases. Seven species of Lutzomyia including L. umbratilis were collected in a plantation of Caribbean pine. Sixty out of 511 female sand flies dissected were positive for flagellates. Among the sand flies from which Leishmania was isolated, promastigotes were observed in the salivary glands and foregut of 13 out of 21 females scored as having very heavy infections in the remainder of the gut, reinforcing the idea that salivary gland invasion may be part of the normal life cycle of Leishmania in nature. Salivary gland infections were detected in specimens of L. umbratilis, L. whitmani and L. spathotrichia. Parasites isolated from L. umbratilis, L. whitmani and also from one specimen of L. dendrophyla containing the remains of a bloodmeal, were compatible with Le. guyanensis by morphology and behaviour in hamsters.

Correlation of male genital filaments and female spermathecal ducts in New World sand flies of the Lutzomyia intermedia species complex (Diptera: Psychodidae, Phlebotominae)

The lengths of the male genital filaments and female spermathecal ducts were measured in phlebotomine sand flies of the Lutzomyia intermedia species complex and the ratios between these characters calculated. Ratios for L. intermedia s. s. from Northeast vs Southeast Brazil (Espírito Santo and Minas Gerais), Espírito Santo/Minas Gerais vs Rio de Janeiro/São Paulo and L. intermedia vs L. neivai were significantly different at P < 0.1, 0.05 and 0.01 respectively when compared using ANOVA. The spermathecal ducts and genital filaments of L. intermedia were significantly longer than those of L. neivai (P < 0.01) and could be used to differentiate these species. The taxonomic and biological significance of these differences is discussed.

Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera, Simuliidae) on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil

The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae); and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

Taxonomic revision of phlebotomine sand fly species in the series davisi and panamensis of the subgenus Psychodopygus Mangabeira, 1941 (Diptera: Psychodidae: Phlebotominae)

Several species of the subgenus Psychodopygus Mangabeira, 1941 are known to be leishmaniosis vectors in Brazil. Some of them are morphologically similar, which makes their identification quite difficult concerning epidemiological studies. The aim of the current work is to study the morphology of adult specimens of the subgenus Psychodopygus, in accordance with the morphological similarity and still taking into account the epidemiological importance of some species. Thus 11 species have been studied, including four subspecies of adult specimens deposited in the phlebotomine collection of Centro de Pesquisas René Rachou-Fiocruz. Morphological characters found in the literature and new features observed in this study were recorded in a taxonomic discussion format. These characters make it easy to separate such species. Four taxa, previously considered as subspecies, were raised to the category of species.

Environmental management for the control of Triatoma dimidiata (Latreille, 1811), (Hemiptera: Reduviidae) in Costa Rica: a pilot project

An ecological control method, using environmental management operations, based on biological and behavioral characteristics of Triatoma dimidiata (Latreille, 1811), was implemented as a pilot project in an area of Costa Rica where the bug is prevalent. The sample was represented by 20 houses with peridomestic colonies (two also had indoor infestation), divided in two equivalent groups of 10 each. In one group we intervened the houses, i.e. all objects or materials that were serving as artificial ecotopes for the bugs were removed, and the second group was used as control houses. After a year of periodic follow up, it became evident that in those houses with a modified environment the number of insects had decreased notoriously even after the first visits and this was more evident after a period of 12.5 to 13.5 months in which no insects were detected in eight of the houses. It also became clear that in this group of houses, recolonization by wild bugs from the surrounding areas, became more difficult, probably due to the absence of protection from bug predators. In the control houses, with the exception of three in which the inhabitants decided to intervene on their own, and another house with a peculiar situation, the insect populations remained the same or even showed a tendency to increase, as confirmed at the end of the experiment. We believe that the method is feasible, low costing and non contaminating. It could be used successfully in other places where T. dimidiata is common and also in countries where other species colonize peridomestic areas of homes. Environmental management of this kind should seek the participation of the members of the communities, in order to make it a more permanent control measure.

Biology of three species of the Meccus phyllosomus complex (Hemiptera: Reduviidae: Triatominae) fed on blood of hens and rabbits

Aspects related to hatching, life time, number of blood meals to molt, mortality, feeding time and postfeed defecation delay for each instar of Meccus phyllosomus, M. mazzottii, and M. bassolsae, life-cycle were evaluated and compared in two cohorts of each of those three species, fed on hens or rabbits. No significant (p > 0.05) differences were recorded among cohorts fed on hens respect to cohorts fed on rabbits in M. phyllosomus and M. mazzottii and the average time of hatching was 21.5 days for cohorts fed on hens and 22.5 for cohorts fed on rabbits. Average egg-to-adult development times were no significant (p > 0.05) different between both cohorts of M. phyllosomus and M. mazzotti, independent of the blood meal source. The average span in days for each instar fed on hens was not significantly different to the average span for each instar fed on rabbits, when comparisons were made by species. The number of blood meals at each nymphal instar varied from 1 to 6 in both cohorts of each species. The mortality rates were higher on older nymphs, in both cohorts of M. phyllosomus and M. bassolsae, whereas they were higher on first instar nymphs on M. mazzottii. Mean feeding time was no significant (p > 0.05) different in triatomines fed on hens or fed on rabbits, when each species were compared separately. A similar number of nymphs of each cohort, completed the cycle. Defecation delay was no significant (p > 0.05) different when cohorts fed on hens and fed on rabbits were compared by species. Most of the studied parameters showed no significant (p > 0.05) differences among those cohorts fed on hens and for fed on rabbits, which could mean a high degree of association of those species with birds as much as mammals, under wild conditions, increasing their capacity to colonize human dwellings.

Activity of Brazilian and Bulgarian propolis against different species of Leishmania

Extracts of propolis samples collected in Brazil and Bulgaria were assayed against four Leishmania species - Leishmania amazonensis, L. braziliensis, L. chagasi from the New World, and L. major from the Old World - associated to different clinical forms of leishmaniasis. The composition of the extracts has been previously characterized by high temperature high resolution gas chromatography coupled to mass spectrometry. Considering the chemical differences among the extracts and the behavior of the parasites, it was observed significant differences in the leishmanicidal activities with IC50/1 day values in the range of 2.8 to 229.3 µg/ml . An overall analysis showed that for all the species evaluated, Bulgarian extracts were more active than the ethanol Brazilian extract. As the assayed propolis extracts have their chemical composition determined it merits further investigation the effect of individual components or their combinations on each Leishmania species.

Biological and genetic aspects of experimental hybrids from species of the Phyllosoma complex (Hemiptera: Reduviidae: Triatominae)

The present work is a thorough investigation of the degree of reproductive isolation between Meccus mazzottii and Meccus longipennis, Meccus picturatus, Meccus pallidipennis and Meccus bassolsae, as well as between M. longipennis and M. picturatus. We examined fertility and segregation of morphological characteristics in two generations of hybrids derived from crosses between these species. The percentage of pairs with (fertile) offspring was highest in the set of crosses between M. longipennis and M. picturatus, and lowest between M. mazzottii and M. picturatus. Most first-generation (F1) individuals from crosses involving M. mazzottii were morphologically similar to this species, while only F1 x F1 progeny of parental crosses between M. mazzottii and M. longipennis had offspring second generation that looked like M. mazzottii. The results indicate that different degrees of reproductive isolation apparently exist among the species of the Phyllosoma complex examined in this study. The biological evidence obtained in this study does not support the proposal that M. longipennis and M. picturatus are full species. It could indicate on the contrary, that both could be considered as subspecies of a single polytypic species. On the other hand, biological evidence supports the proposal that M. mazzottii is a full species.

Vector density and the control of kala-azar in Bihar, India

Bihar, India has been in the grip of kala-azar for many years. Its rampant and severe spread has made life miserable in most parts of the state. Such conditions require a comprehensive understanding of this affliction. The numbers coming out of the districts prone to the disease in the north and south Ganges have provided us with several startling revelations, as there are striking uniformities on both sides, including similar vegetation, water storage facilities, house construction and little change in risk factors. The northern areas have been regularly sprayed with DDT since 1977, but eradication of the disease appears to be a distant dream. In 2007 alone, there were as many as 37,738 cases in that region. In contrast, the southern districts of Patna and Nalanda have never had the disease in its epidemic form and endemic disease has been present in only some pockets of the two districts. In those cases, two rounds of spraying with DDT had very positive results, with successful control and no new established foci. In addition, an eleven-year longitudinal study of the man hour density and house index for the vector Phlebotomus argentipes demonstrated that they were quite high in Patna and Nalanda and quite low in north Bihar. Given these facts, an attempt has been made to unravel the role of P. argentipes saliva (salivary gland) in the epidemiology of kala-azar. It was determined that patchy DDT spraying should be avoided for effective control of kala-azar.

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.

CA88, a nuclear repetitive DNA sequence identified in Schistosoma mansoni, aids in the genotyping of nine Schistosoma species of medical and veterinary importance

CA88 is the first long nuclear repetitive DNA sequence identified in the blood fluke, Schistosoma mansoni. The assembled S. mansoni sequence, which contains the CA88 repeat, has 8,887 nucleotides and at least three repeat units of approximately 360 bp. In addition, CA88 also possesses an internal CA microsatellite, identified as SmBr18. Both PCR and BLAST analysis have been used to analyse and confirm the CA88 sequence in other S. mansoni sequences in the public database. PCR-acquired nuclear repetitive DNA sequence profiles from nine Schistosoma species were used to classify this organism into four genotypes. Included among the nine species analysed were five sequences of both African and Asian lineages that are known to infect humans. Within these genotypes, three of them refer to recognised species groups. A panel of four microsatellite loci, including SmBr18 and three previously published loci, has been used to characterise the nine Schistosoma species. Each species has been identified and classified based on its CA88 DNA fingerprint profile. Furthermore, microsatellite sequences and intra-specific variation have also been observed within the nine Schistosoma species sequences. Taken together, these results support the use of these markers in studying the population dynamics of Schistosoma isolates from endemic areas and also provide new methods for investigating the relationships between different populations of parasites. In addition, these data also indicate that Schistosoma magrebowiei is not a sister taxon to Schistosoma mattheei, prompting a new designation to a basal clade.

The role of population movement in the epidemiology and control of schistosomiasis in Brazil: a preliminary typology of population movement

This paper examines recent developments in migration studies. It reviews literature related to the potential role of internal population movement in the occurrence of schistosomiasis in Brazil and modifies Prothero's typology of population movement for use in Brazil. This modified classification system may contribute to a better understanding of schistosome transmission as well as improved research and control programs. The results of this study indicate that population movement in Brazil primarily involves economically-motivated rural-urban and interregional movement. However, several movement patterns have become increasingly important in recent years as a result of changing socioeconomic and urbanisation dynamics. These patterns include urban-urban, intracity and urban-rural movement as well as the movement of environmental refugees and tourists. Little is known about the epidemiological significance of these patterns. This paper also highlights the role of social networks in the decision to migrate and to settle. Prothero's classic population movement typology categorises movement as either one-way migrations or circulations and examines them along spatial and temporal scales. However, the typology must be modified as epidemiological information about new patterns becomes available. This paper identifies areas that require further research and offers recommendations that can improve the measurement and spatial analysis of the relationship between population movement and schistosomiasis.

Control of Mycobacterium fortuitum and Mycobacterium intracellulare infections with respect to distinct granuloma formations in livers of BALB/c mice

Mycobacterium fortuitum is a rapidly growing nontuberculous Mycobacterium that can cause a range of diseases in humans. Complications from M. fortuitum infection have been associated with numerous surgical procedures. A protective immune response against pathogenic mycobacterial infections is dependent on the granuloma formation. Within the granuloma, the macrophage effector response can inhibit bacterial replication and mediate the intracellular killing of bacteria. The granulomatous responses of BALB/c mice to rapidly and slowly growing mycobacteria were assessed in vivo and the bacterial loads in spleens and livers from M. fortuitum and Mycobacterium intracellulare-infected mice, as well as the number and size of granulomas in liver sections, were quantified. Bacterial loads were found to be approximately two times lower in M. fortuitum-infected mice than in M. intracellulare-infected mice and M. fortuitum-infected mice presented fewer granulomas compared to M. intracellulare-infected mice. These granulomas were characterized by the presence of Mac-1+ and CD4+ cells. Additionally, IFN-γmRNA expression was higher in the livers of M. fortuitum-infected mice than in those of M. intracellulare-infected mice. These data clearly show that mice are more capable of controlling an infection with M. fortuitum than M. intracellulare. This capacity is likely related to distinct granuloma formations in mice infected with M. fortuitum but not with M. intracellulare.

Molecular phylogeny of the Myzorhynchella Section of Anopheles (Nyssorhynchus) (Diptera: Culicidae): genetic support for recently described and resurrected species

Phylogenetic relationships among species of the Myzorhynchella Section of Anopheles (Nyssorhynchus) were investigated using the nuclear ribosomal DNA second internal transcribed spacer (ITS2), the nuclear whitegene and mitochondrial cytochrome oxidase subunit I (COI) regions. The recently described Anopheles pristinus and resurrected Anopheles guarani were also included in the study. Bayesian phylogenetic analyses found Anopheles parvus to be the most distantly related species within the Section, a finding that is consistent with morphology. An. pristinus and An. guarani were clearly resolved from Anopheles antunesi and Anopheles lutzii, respectively. An. lutzii collected in the same mountain range as the type locality were found within a strongly supported clade, whereas individuals from the southern state of Rio Grande do Sul, tentatively identified as An. lutzii based on adult female external morphology, were distinct from An. lutzii, An. antunesi and from each other, and may therefore represent two new sympatric species. A more detailed examination of An. lutzii sensu latoalong its known geographic range is recommended to resolve these anomalous relationships.