ABSTRACT
Evolutionary relationships among parasites of the subfamily Leishmaniinae, which comprises pathogen agents of leishmaniasis, were inferred based on differential protein expression profiles from mass spectrometry-based quantitative data using the PhyloQuant method. Evolutionary distances following identification and quantification of protein and peptide abundances using Proteome Discoverer and MaxQuant software were estimated for 11 species from six Leishmaniinae genera. Results clustered all dixenous species of the genus Leishmania, subgenera L. (Leishmania), L. (Viannia), and L. (Mundinia), sister to the dixenous species of genera Endotrypanum and Porcisia. Placed basal to the assemblage formed by all these parasites were the species of genera Zelonia, Crithidia, and Leptomonas, so far described as monoxenous of insects although eventually reported from humans. Inferences based on protein expression profiles were congruent with currently established phylogeny using DNA sequences. Our results reinforce PhyloQuant as a valuable approach to infer evolutionary relationships within Leishmaniinae, which is comprised of very tightly related trypanosomatids that are just beginning to be phylogenetically unraveled. In addition to evolutionary history, mapping of species-specific protein expression is paramount to understand differences in infection processes, tissue tropisms, potential to jump from insects to vertebrates including humans, and targets for species-specific diagnostic and drug development.
ABSTRACT
There are rare individuals whose insatiable curiosity and boundless intellect propel them into multiple frontiers of science, leaving an indelible mark on the fields that they venture into [...].
ABSTRACT
Molecular methods have been responsible for a notable increase in the detection of Leishmaniinae infections in wild animals. Determining their infectiousness is of paramount importance in evaluating their epidemiological significance. One of the most efficient ways of determining infectiousness for vector borne diseases is xenodiagnosis with the appropriate vector. However, this is logistically very difficult to accomplish in the field, and an ideal solution is to find a molecular surrogate for xenodiagnosis. In this review we discuss different approaches to the problem by focusing on the infectiousness of Leishmania (Viannia) braziliensis in rodents under laboratory and field conditions. Comparisons with similar studies for other Leishmania species emphasizes that there are pivotal differences in the infectiousness and the importance of asymptomatic infections in different hosts. Potentially the most promising surrogate is the real time quantitative PCR (qPCR). However, its success depends on choosing a tissue that relates to the vector's feeding location and the parasite's tissue tropism. This requires detailed knowledge of the infection of each species in its wild hosts. We conclude that for L. (V.) braziliensis infections in wild rodents the tissue of choice for a molecular xenodiagnostic test, based on the qPCR is blood, providing that a significant number of samples must be examined.
Subject(s)
Leishmania braziliensis , Leishmania , Leishmaniasis, Cutaneous , Leishmaniasis , Animals , Leishmania braziliensis/genetics , Rodentia , Leishmania/genetics , Real-Time Polymerase Chain Reaction , Leishmaniasis, Cutaneous/diagnosis , Leishmaniasis, Cutaneous/veterinaryABSTRACT
BACKGROUND: Human and wild rodent infection rates with Leishmania (Viannia) braziliensis are needed to differentiate transmission pathways in anthropogenically altered habitats. METHODS: Human participants in northeast Brazil were tested by the leishmanin skin test (LST) and inspected for lesions/scars characteristic of American clinical leishmaniasis (ACL). Molecular (PCR/qPCR) test records of free-ranging rodents were available from a concurrent capture-mark-recapture study. Force of Infection (λ) and recovery (ρ) rates were estimated from cross-sectional and longitudinal datasets. RESULTS: Cumulative prevalences of human LST+ves and ACL scar+ves were 0.343-0.563 (n = 503 participants) and 0.122-0.475 (n = 503), respectively. Active ACL lesions were not detected. Annual rates of LST conversions were λ = 0.03-0.15 and ρ = 0.02-0.07. The probability of infection was independent of sex and associated with increasing age in addition to the period of exposure. Rodents (n = 596 individuals of 6 species) showed high rates of exclusively asymptomatic infection (λ = 0.222/month) and potential infectiousness to the sand fly vector. Spatially concurrent rodent and household human infection prevalences were correlated. CONCLUSIONS: Human exposure to L. (V.) braziliensis continues to be high despite the substantial drop in reported ACL cases in recent years. Spill-over transmission risk to humans from rodents in peridomestic habitats is likely supported by a rodent infection/transmission corridor linking houses, plantations, and the Atlantic Forest.
ABSTRACT
The Leishmaniinae subfamily of the Trypanosomatidae contains both genus Zelonia (monoxenous) and Endotrypanum (dixenous). They are amongst the nearest known relatives of Leishmania, which comprises many human pathogens widespread in the developing world. These closely related lineages are models for the genomic biology of monoxenous and dixenous parasites. Herein, we used comparative genomics to identify the orthologous groups (OGs) shared among 26 Leishmaniinae species to investigate gene family expansion/contraction and applied two phylogenomic approaches to confirm relationships within the subfamily. The Endotrypanum monterogeii and Zelonia costaricensis genomes were assembled, with sizes of 29.9 Mb and 38.0 Mb and 9.711 and 12.201 predicted protein-coding genes, respectively. The genome of E. monterogeii displayed a higher number of multicopy cell surface protein families, including glycoprotein 63 and glycoprotein 46, compared to Leishmania spp. The genome of Z. costaricensis presents expansions of BT1 and amino acid transporters and proteins containing leucine-rich repeat domains, as well as a loss of ABC-type transporters. In total, 415 and 85 lineage-specific OGs were identified in Z. costaricensis and E. monterogeii. The evolutionary relationships within the subfamily were confirmed using the supermatrix (3384 protein-coding genes) and supertree methods. Overall, this study showed new expansions of multigene families in monoxenous and dixenous parasites of the subfamily Leishmaniinae.
ABSTRACT
ABSTRACT Molecular methods have been responsible for a notable increase in the detection of Leishmaniinae infections in wild animals. Determining their infectiousness is of paramount importance in evaluating their epidemiological significance. One of the most efficient ways of determining infectiousness for vector borne diseases is xenodiagnosis with the appropriate vector. However, this is logistically very difficult to accomplish in the field, and an ideal solution is to find a molecular surrogate for xenodiagnosis. In this review we discuss different approaches to the problem by focusing on the infectiousness of Leishmania (Viannia) braziliensis in rodents under laboratory and field conditions. Comparisons with similar studies for other Leishmania species emphasizes that there are pivotal differences in the infectiousness and the importance of asymptomatic infections in different hosts. Potentially the most promising surrogate is the real time quantitative PCR (qPCR). However, its success depends on choosing a tissue that relates to the vector's feeding location and the parasite's tissue tropism. This requires detailed knowledge of the infection of each species in its wild hosts. We conclude that for L. (V.) braziliensis infections in wild rodents the tissue of choice for a molecular xenodiagnostic test, based on the qPCR is blood, providing that a significant number of samples must be examined.
ABSTRACT
A group of 18 research workers involved in different aspects of the biology of Lutzomyia longipalpis discussed whether or not it is important to give taxonomically valid names to populations that have been defined by biological, biochemical and molecular methods to be reproductively isolated. The type material of this medically important species has been lost and because of this it was recommended that a colony should be established from insects captured in the region of the type area and that their description should serve as the basis for future descriptions. It was pointed out that there is a lack of uniformity in the naming of closely related American sand flies and that some of the differences between populations of Lu. longipalpis are greater than those between accepted species. The majority of the participants agreed that the populations that have been defined in the literature as sibling species should be named.
Subject(s)
Animals , Insect Vectors/classification , Psychodidae/classification , ClassificationABSTRACT
Sand flies were collected in the central region of the state of Rondônia (W 64 30' to 63 00' and S 10 00'to 11 00') using Shannon and CDC light traps from October 1997 to August 2000. A total of 85,850 specimens representing 78 named species were captured. Of these 14 were new records for Rondônia. The proportion of males/females was 1/1.131. Trypanosomatids, that are presently being identified, were detected in 11 species. Leishmania (Viannia) naiffi was recorded from Psychodopygus davisi and P. hirsutus. In the present study the dominant species was P. davisi (39.6 percent) followed by Lutzomyia whitmani (13.1 percent), P. carrerai (11.6 percent), and P. hirsutus (10.2 percent). The importance of P. davisi as a vector of zoonotic cutaneous leishmaniasis is discussed
Subject(s)
Animals , Humans , Male , Female , Insect Vectors , Psychodidae , Brazil , Insect Vectors , Leishmaniasis, Cutaneous , Population Density , Psychodidae , SeasonsABSTRACT
The direct agglutination test (DAT) was evaluated for serodiagnosis of visceral leishmaniasis (VL) in human and canids (dogs and foxes Cerdocyon thous). The results were compared with those of the immunofluorescent antibody assay (IFAT) and enzyme-linked immunosorbent assay (ELISA). The sera used were from: humans (303): confirmed VL (16), suspected VL (65), other conditions (102), negative controls (15) and individuals from an endemic area (105); dogs (82): from an endemic area (68), Salvaterra/Marajó/Pará (21 of which were parasitologically positive), and negative controls (14), from Belém; foxes (9): caught on Marajó Island. Antigens for DAT were prepared from promastigots of L. (L.) donovani, L. (L.) chagasi. Antigens used in ELISA and IFAT were prepared from promastigotes (soluble antigen) and amastigotes respectively of L. (L.) chagasi. In humans, the specificity and sensitivity of DAT using L. (L.) donovani were high (98.4 per cent and 100 per cent respectively) and comparable to that of IFAT (97.5 per cent and 100 per cent). ELISA was less specific (84.8 per cent) although similarly sensitive (100 per cent). In dogs, DAT was more specific using L. (L.) donovani as antigen than using L. (L.) chagasi. However, both DAT and ELISA were less sensitive (both 71.4 per cent) than IFAT (100 per cent). This difference was reflected in the results from endemic dogs, 87 per centof which were positive by IFAT but only 54 per cent by ELISA and 49 per cent by DAT. Similarly, all 9 fox sera were positive by IFAT, 7 of 9 (78 per cent) by ELISA but none by DAT. In conclusion, DAT using L. (L.) donovani antigen can provide a useful test for human VL; utilization on a large scale would be possible with a suitable reference laboratory to monitor antigen quality. However, DAT appears less useful for canine studies, as it was less sensitive than ELISA and especially IFAT in detecting canine infection.
Subject(s)
Humans , Animals , Dogs , Agglutination Tests , Leishmaniasis, Visceral/diagnosis , Antigens, Protozoan/immunology , Brazil , Dog Diseases/diagnosis , Dog Diseases/immunology , Enzyme-Linked Immunosorbent Assay , Fluorescent Antibody Technique, Indirect , Foxes , Leishmaniasis, Visceral/immunology , Leishmaniasis, Visceral/veterinary , Leishmania/growth & development , Leishmania/immunologyABSTRACT
The application of different taxonomic methods (Cladistic, Evolutionary Taxonomy and Numerical Taxonomy) to the taxonomy of the Genus Leishmania are reviewed. The major groupings of the most recent classifications obtained using the cladistical approach agree with the major divisions of previous classifications which used traditional taxonomy (Evolutionary Taxonomy). The advantage of the cladistical approach is that it produces cladograms whose branches indicate more accurately levels of relationships between the different taxa. Numerical Taxonomy is useful for identification but not as good as the cladistical approach for classification. The ancient division of this monophyletic genus into two major evolutionary lines supports the use of the subgeneric names Leishmania and Viannia.
Subject(s)
Animals , Classification/methods , Leishmania/classification , CongressABSTRACT
Em área endêmica de leishmaniose tegumentar americana no Município de Jussara, Estado do Paraná, Brasil, detectaram-se três cäes domésticos infectados por Leishmania (Viannia) brasiliensis
Subject(s)
Dogs , Cricetinae , Animals , Leishmaniasis/epidemiology , Leishmania/isolation & purification , Brazil , Leishmaniasis/transmission , Leishmaniasis/veterinary , Dog Diseases , Disease Reservoirs/veterinaryABSTRACT
Estudaram-se os aspectos histopatológicos relativos à evoluçäo da infecçäo experimental produzida em Cebus apella (Primates: Cebidae) por Leishmania (V.) lainsoni, L. (V.) braziliensis e L. (L.) amazonensis. O exame microscópico de biópsias seqüênciais, obtidas dos animais a intervalos definidos d etempo (a primeira, âs 48 ou 72 horas após a inoculaçäo, e as seguintes, a cada 30 dias), mostrou que o desenvolvimento das lesöes, independente da espécie de Leishmania inoculada, pass por uma seqüência de etapas a nível tecidual - 1) infiltrado inespecífico crônico; 2) nódulo macrofágico (com numerosos parasitas); 3) necrose das células parasitadas; 4) granuloma epitelióide; 5) absorçäo da área necrosada (às vezes formando granuloma de corpo estranho); 6) infiltrado inespecífico crônico residual); e 7) cicatrizaçäo - que representaria a formaçäo e a resoluçäo das lesöes. Discutiram-se também os prováveis mecanismso imunopatológicos que determinaram esta seqüência de eventos e sua possível semelhança com a evoluçäo das lesöes na leishmaniose tegumentar humana
Subject(s)
Animals , Male , Female , Leishmania braziliensis/pathogenicity , Leishmania mexicana/pathogenicity , Leishmaniasis/pathology , Biopsy , Cebus , Disease Models, AnimalABSTRACT
Eimeria vitellini n. sp. is described from the faeces of the Rhamphastos v. vitellinus. Oocysts broadly ellipsoidal to oval (egg-shaped), 22,6 x 18.3 (20.0-25.0 x 16.3-22.5) micronm, shapeindex (length/width) 1.2 (1.1-1.1). Oocyst wall a single colourless layer about 0.5 micronm thick, becoming thinner at one ectremity, at which point the oocyst usually ruptures. No oocyst residuum, but 1 or 2 small polr bodies of about 1.0-1.5 x 0.5-1.0 micronm. Sporocysts ellongated ellipsoid (pearshaped), 14.3 x 7.5 (13.8-15.0 x 6.9-7.5) micronm, shape-index (1.9 (1.8-2.0), with a thin colourless wall bearing a very delicate Stieda body: a conspicuous sub-Stieda body is present. Sporozoites with anterior and posterior regractile bodies and strongly recurved around a bulky, compact sporocyst residuum composed of relatively fine granules and spherules
Subject(s)
Animals , Birds/parasitology , Eimeria/anatomy & histology , Brazil , Eimeria/classificationABSTRACT
Objetivando avaliar o potencial do primata C. apella como modelo experimental da leishmaniose cutânea produzida pela L. (V.) brasiliensis e L. (L.) amazonensis, inocularam-se, via intradérmica, 3 X10**6 de promastigotas dessas leishmanias, em 8 sítios da cauda de 10 espécimens desse desse primata, 5 deles com a L. (V.) braziliensis e outros 5 com a L. (L.) amazonensis. Posteriormente, às inoculaçöes, o exame semanal dos animais e biópsias mensais, revelaram os seguintes resultados relativos a cada parasita: a) L. (V.) brasiliensis: o periodo de incubaçäo foi d e15-20 dias; aos 30 dias evidenciaram-se lesöes pápulo-eritematosas, que evoluiram para nódulo ao fim de 60 dias; no 3§ mês, notou-se espontânea destas lesöes e, no 4§ mês, deu-se o inicio da reparaçäo das lesöes ulceradas, culminando com a cura em um dos animais após 5 meses, em dois após 6 meses, noutro após 7 meses e, no ultimo, após 10 meses. Quanto ao parasitismo nas lesöes, foi demonstrado nos 5 animais, até 90 dias; depois disto, somente em 2 até 120 dias e, por fim, até 180 dias apenas naquele que curou depois de 10 meses. b) L. (L.) amazonensis: o período de incubaçäo foi de 20 dias; aos 30 dias notou-se lesöes pápulo-eritematosas, que também evoluiram para nódulos ao fim de 60 dias, porém, a partir do 3§ mês, estas lesöes regrediram rapidamente ao fim de 90 dias, quando näo mais detectou-se o parasita na pele dos animais. Em relaçäo aos testes de Montenegro, somente 2 dos 5 animais infectados com a L. (V.) braziliensis reagiram ao teste, 6 e 90 dias após as inoculaçöes. Os resultados observados permitiram confirmar a infectividade do C. apella a estas leishmanias e, também, reforçar a indicaçäo desse primata como modelo experimental da leishmaniose cutânea por estes parasitas
Subject(s)
Animals , Male , Female , Leishmaniasis/complications , CebusABSTRACT
Foi investigada a susceptibilidade do primata Cebus apella (Cebidae) à infecçäo experimentada pela Leishmania (Viannia) lainsoni, com o objetivo de estudar a patogenia desse parasita, ainda pouco conhecido para o homem. Desse forma, cinco espécimes jovens daquele primata, 2 machos e 3 fêmeas, foram inoculados, itraderme, em oito sítios diferentes da regiäo dorsal da cauda com 3 x 10***6 de promastigotas do parasita (MHOM/BR/81/M6426, Benevides, Pará), obtidas de cultura da fase estacionária. Em seguida às inoculaçöes, a infecçäo experimental no animais foi comprovada, näo só pela presença de amastigotas do parasita na pele dos animais inoculados, mas, também, pela concomitância desse achado associado ao desenvolvimento de lesäo cutânea nos pontos da pele onde o parasita foi inoculado. Diante desses resultados, ficou demonstrada a susceptibilidade do primata Cebus apella à infecçäo experimental pela leishmania lainsoni, cujo período de infecçäo durou quese quatro meses, suficiente para testar drogas antileishmanióticas e estudar a patogênese da doença causada por este parasita