Canine visceral leishmaniasis in Rio de Janeiro, Brazil. Clinical, parasitological, therapeutical and epidemiological findings (1977-1983)

Forty dogs from the periphery of the city of Rio de Janeiro were studied. All dogs where diagnosed as positive for leishmaniasis either parasitologically and/or serologically. Among them, 19 came from areas where only Visceral Leishmaniasis (VL) occurs (Realengo, Bangu, Senador Camará). Clinical signs of the disease were seen in 36.8% of the cases, including emaciation - 100%, lymphadenopathy and depilation - 85.7%. The other 21 dogs came from an area (Campo Grande) where both diseases (VL, and American Cutaneous Leishmaniasis - ACL) occur. Clinical signs of the disease, mainly cutaneous or mucocutaneous ulcers were seen in 76.2% of the cases. Leishmania parasites were found in 39 cases: 22% in viscera, 42.5% in viscera and normal skin and 35% in cutaneous or mucocutaneous ulcers. All the Leishmania stocks isolated from dogs which came from Realengo, Bangu, Senador Camará (VL area), and from Campo Grande (VL + ACL area) were characterized as L. donovani (except in one case) according to their schizodeme, zymodeme and serodeme. The only stock characterized as L. b. braziliensis, was isolated from the lymph node of a dog from Campo Grande with visceral disease and without skin lesions. Antimony therapy attempted in eight Leishmania donovani positive dogs was unsuccessful.     

Canine leishmaniasis in Campania: new and old foci

Canine Leishmaniasis (CanL) is endemic in Campania Region (Italy) and is strictly related to Human Visceral Leishmaniasis. Past and present reports of the prevalence in the Region show that exist places were CanL has been known for a century (Vesuvius and Ischia Foci) and other localities where the disease appears to be recent (Caserta and Salerno provinces); moreover, the zoonosis is seen not only in endemic foci (autochthonous), but also in non-endemic areas (imported cases), for example in the Benevento and Avellino provinces. Two zymodemes have been identified in human and canine population and also in sandflies: MON 1 and MON 72. Endemic or stable CanL foci correspond with Vesuvius Area, Ischia island, Maddaloni and neighbouring Commons, other foci in the Salerno province. These foci are associated with optimal ecological condition, abundance of reservoirs and hosts, abundance of phlebotomine vectors, prevalence in canine population around 10-40%, incidence in canine population 5%, risk for human population 0.002%. Instable foci occur at the border of the stable foci: they may be the result of changes in climate with the occasional introduction of infected dogs in the areas; in the foci are registered low presence of phlebotomine vectors, prevalence around 0.5-3%, sporadic human cases. Today, in Campania region CanL undoubtedly has an increased incidence and a wider geographic distribution than before: new cases are now reported in areas that were previously non-endemic. Ecological, demographic and environmental changes, large population movements, urbanization have led to an increased incidence and to importation into suburbs with high densities of people and sand-flies. These changes include "global warming", increased number of stray dogs, dogs and population movements, changes in human population (increased number of immune-depressed and old people). Nowadays, the most important focus of CanL and Human Visceral Leishmaniasis of the Mediterranean area is located in Campania Region: during the year 2000, 143 cases of Human Visceral Leishmaniasis have been recorded in Italy, an half of them (83 cases) in Campania region.     

Evaluation of serological assays based on a novel excreted antigen preparation for the diagnosis of Cutaneous Leishmaniasis in Panama

The objective of the present study was to determine the efficacy of prototype diagnostic serological assays for American Cutaneous Leishmaniasis (ACL) in Panama. As such, we prospectively sampled 100 cutaneous leishmaniasis case-patients and tested their sera in two serological assays based upon novel soluble antigen preparations made from propagating the parasites in a protein-free, serum free media. Using serum and a Leishmania mexicana antigen preparation to sensitize plates, the assay correctly identified 89% of the case-patients. While using serum with an antigen preparation from Leishmania braziliensis, the assay correctly identified 71% of the patients. Concerning both test formats, performance was near equal in true positive and presumptive positive subsets demonstrating the improved sensitivity of these assays over reference methods of choice. Since the incidence of leishmaniasis in Panama has increased dramatically in the past 10 years, these assays may be useful in clinical and epidemiological studies and control programs.     

KDNA Genetic Signatures Obtained by LSSP-PCR Analysis of Leishmania (Leishmania) infantum Isolated from the New and the Old World

Background

Visceral Leishmaniasis (VL) caused by species from the Leishmania donovani complex is the most severe form of the disease, lethal if untreated. VL caused by Leishmania infantum is a zoonosis with an increasing number of human cases and millions of dogs infected in the Old and the New World. In this study, L. infantum (syn. L.chagasi) strains were isolated from human and canine VL cases. The strains were obtained from endemic areas from Brazil and Portugal and their genetic polymorphism was ascertained using the LSSP-PCR (Low-Stringency Single Specific Primer PCR) technique for analyzing the kinetoplastid DNA (kDNA) minicircles hypervariable region.

Principal Findings

KDNA genetic signatures obtained by minicircle LSSP-PCR analysis of forty L. infantum strains allowed the grouping of strains in several clades. Furthermore, LSSP-PCR profiles of L. infantum subpopulations were closely related to the host origin (human or canine). To our knowledge this is the first study which used this technique to compare genetic polymorphisms among strains of L. infantum originated from both the Old and the New World.

Conclusions

LSSP-PCR profiles obtained by analysis of L. infantum kDNA hypervariable region of parasites isolated from human cases and infected dogs from Brazil and Portugal exhibited a genetic correlation among isolates originated from the same reservoir, human or canine. However, no association has been detected among the kDNA signatures and the geographical origin of L. infantum strains.     

Interpretation of laboratory data during cryptic leishmaniasis in dog

Leishmaniasis is a zoonosis caused by an intracellular parasite belonging to the genus Leishmania. In Europe, Africa, South America and China, visceral leishmaniasis is caused by L. infantum. The vectors of leishmaniasis are phlebotomine sandflies belonging to the genera Phlebotomus. According to the World Health Organization there are 2 million new cases each year and 1/10 of the world's population is at risk of infection. Leishmaniasis is considered a zoonosis and human are generally accidental hosts. The animal reservoir includes rodents, dog and other mammals. Several studies have indicate that half of the dogs with antileishmanial antibodies have no signs of disease although, animal with subclinical infections are potentially infectious to sand flies. The factors determining susceptibility or resistence to visceral leishmaniasis remain unclear, but the genetics of the host may play a major role. Clinical signs are: intermittent fever, hepatosplenomegaly, skin lesions and ulcers, alopecia, onychogryphosis, anemia, thrombocytopenia and hypergammaglobulinemia. In mice, the outcome of infection depends on the polarized activation of one of two subsets of CD4+ T cells, Th1 or Th2, the subdivision into Th1 and Th2 cells is based on the pattern of cytokines that they produce. Th1 cells produce gamma interferon (IFN-gamma) and interleukin -2 (IL-2), whereas Th2 cells produce IL-4, IL-5, and IL-10. An important difference between susceptible and resistant mice is that the resistant mice are able to switch to a Th1 profile and control the disease. An important factor in the "decision" to form a Th1 or Th2 phenotype is the early cytokine environment, and IL-12 is one of the cytokines that contributes significantly to the establishment of the Th1 phenotype. Canine leishmaniosis is endemic in the Mediterranean basin and, in most cases is caused by the parasite Leishmania infantum. The main clinical findings are skin lesions, local or generalized lymphoadenopathy, loss of body weight, glomerulopathy, ocular lesions, epistaxis and lameness. Non pruritic skin lesions are the usual manifestation and several forms have been described, such as exfoliative dermatitis and alopecia, and ulcerative, nodular and pustular dermatitis. Seroepidemiological studies of canine leishmaniasis have revealed a large number of asymptomatic seropositive animals. Moreover in areas where leishmaniasis is highly endemic, high proportion of apparently healthy animals show low levels of anti-Leishmania antibodies. Others have regressive forms of the desease, and their antibody levels will decrease in the following months or years; still others maintain low levels of antibodies without developing the desease for many years. However, the total number of infected animals is unknown. Canine leishmaniasis is a major zoonosic parasitic disease, enzootic in the Mediterranean area, caused by the intracellular protozoan Leishmania infantum. The dog is the main reservoir host of the parasite. However, most infected dogs do not present any clinical signs, and there is evidence that Leishmania infection prevalence rates in areas of endemicity are higher than those ascertained by serological studies. Visceral leishmaniasis is becoming a real problem of public health because it is an opportunistic infection in immunocompromised patients and in human immunodeficiency virus-positive subjects. The detection of the extent of the infection, particularly among asymptomatic dogs, is of great importance for the control of leishmaniasis. PCR has been applied successfully in recent years to detect Leishmania spp. even in the cases with any of the clinical manifestation of leishmaniasis. Very recently, real-time PCR for Leishmania has been applied to evaluate the parasitic load of dog tissues both at the time of the diagnosis and during follow-up of the therapy and to measure cytokine mRNA levels in different clinical samples of infected and uninfected dogs.     

Study of an outbreak of cutaneous leishmaniasis in Venezuela. The role of domestic animals

During an outbreak of cutaneous leishmaniasis in a locality (Las Rosas, Cojedes State, Venezuela) previously non-endemic, 12.9% of humans, 7% of dogs and 21.4% of donkeys (Equus asinus) had lesions with parasites. The agent in the three hosts was identified as Leishmania braziliensis, subspecies braziliensis at least in man and donkey. The probable vector was Lutzomyia panamensis. No infection was found in a small sample of wild mammals examined. The outbreak was apparently linked with the importation of donkeys with ulcers, from endemic areas. The authors call attention to the fact that not only in the foci of "uta", but also in areas of the other forms of American cutaneous leishmaniasis, dogs are frequently found infected. They emphasize the necessity of searching for the infection in donkeys and of performing hemocultures and xenodiagnosis with sandflies in human, canine and equine cases, to verify their possible role as sources of infection, and not merely as dead ends in the epidemiological chain of the disease.     

Schizodeme and zymodeme characterization of Leishmania in the investigation of foci of visceral and cutaneous leishmaniasis

Leishmania parasites were isolated from humans and canines in foci of cutaneous and visceral leishmaniasis. After in vitro cultivation the parasites were examined by the following biochemical techniques: (i) restriction analysis of kinetoplast DNA (kDNA) also known as schizodeme analysis (Morel et al., 1980); (ii) zymodeme analysis (Barret et al., 1980); by agarose gel electrophoresis and (iii) isoelectricfocusing in polyacrylamide gels. The strains of cutaneous and visceralizing leishmanias studied could be differentiated by schizodeme analysis, using the endonuclease MspI, into three complexes agreeing with those accepted for human New World leishmaniasis. In the municipality of Rio de Janeiro, isolates from a focus of cutaneous leishmaniasis were identified as L. braziliensis braziliensis and from a focus of visceral leishmaniasis were identified as L. donovani by zymodeme characterization. Identical restriction enzyme profiles of kDNA from human and canine isolates indicated that in the cutaneous focus at Jacarepaguá, Rio de Janeiro, the same strain was probably circulating in both the canine and human populations. This suggests a possible role for dogs as a reservoir host for L. braziliensis braziliensis. In addition, our results confirm the importance of dogs as reservoirs in visceral leishmaniasis. The stability of the electrophoretic patterns of restriction digest ("fingerprints") of Leishmania kDNA as well as differences in the sensitivity of the techniques used were demonstrated. Strains from widely different geographical areas as well as strains maintained in vivo and in vitro showed identical kDNA restriction patterns, while strains showing similar banding patterns by enzyme electrophoresis could be differentiated by schizodeme analysis. These results demonstrate the usefulness of an integrated biochemical approach in the identification of Leishmania.     

An outbreak of American cutaneous leishmaniasis (Leishmania braziliensis braziliensis) in a periurban area of Rio de Janeiro city, Brazil: clinical and epidemiological studies

From July 1984 to September 1986, 105 cases of American cutaneous leishmaniasis were studied in a locality closely situated to an urbanized area of the city of Rio de Janeiro, Brazil. Settlement in this area was established at least 20 years ago but the first cases were noted six months prior to the beginning of this study. Cases were almost exclusively cutaneous and ulcerated, with one to six months of evolution. Montenegro's skin tests were positive in all cases and anti-Leishmania antibodies were detected by indirect immunofluorescence test in 74.3% of the patients. Parasites were demonstrated in 69.5% of cases. Domestic animals were easily found infected: 32% of the examined dogs and 30.8% of the examined equines were positive to the presence of Leishmania in cutaneous ulcerated lesions. Parasite isolates from human, dog and equines were immunologically characterized and identified as L. b. braziliensis. 73.0% of the sandfly population were Lutzomyia intermedia mainly caught on human baits and on domestic animals. Our observations suggest that this is an area of recent established L. b. braziliensis infection and that transmission probably occurs indoors or outdoors close to the houses.     

Isolation and isoenzyme characterization of Leishmania (Viannia) braziliensis from a case of human cutaneous leishmaniasis in northeast centre of the state of São Paulo

The diagnosis of human cutaneous leishmaniasis in small towns is sometimes made without the species identification of the Leishmania, even in areas without previous epidemiological surveys. Here we report the isolation of a Leishmania strain from a patient of Rinc?o, state of S?o Paulo, that was identified by isoenzyme characterization as L. (Viannia) braziliensis. Sand fly collections were made in the area where the patient live in order to investigate the likely vector species.     

Leishmaniasis vector potential of Lutzomyia spp. in Colombian coffee plantations

Potential vectors of Leishmania braziliensis Vianna were assessed at four study sites in the mountainous Valle del Cauca, western Colombia, from March to June 1989. In an active focus of transmission at 1450 m altitude, a coffee plantation at Versalles, there were high densities of antropophilic phlebotomines: Lutzomyia columbiana (Ritorcelli & Van Ty) and Lu.townsendi (Ortiz), both in the verrucarum species group, and of Lu.pia (Fairchild & Hertig). At a comparable altitude in a forest reserve at Yotoco where leishmaniasis is unknown, Lu.pia was the prevalent species and Lu.townsendi was absent. In two localities at 1150 m altitude, there were plentiful Lu.lichyi (Floch & Abonnenc) plus both species in the verrucarum group, but Lu.pia was absent. One of these localities, a coffee plantation at Villa Hermosa where a leishmaniasis outbreak occurred in 1986, was compared with a leishmaniasis-free, partly wooded nature reserve at Mateguadua. No natural infections of Leishmania were found in a total of 1896 wild-caught female phlebotomines belonging to at least seven species. It remains unclear why Leishmaniasis transmission is associated with coffee plantations in this part of Colombia. Laboratory-bred Lu.lichyi females were invariably autogenous, and blood-seeking females of this species were always parous. Parity rates in wild-caught females of other species were 55% Lu.pia, 24% Lu.columbiana and 14% Lu.townsendi. Female Lutzomyia infected artificially with Le.braziliensis promastigotes developed peripylarian infections. Higher proportions of Lu.townsendi (96%) and Lu.columbiana (78%) became infected but these species developed lower rates of stomodaeal infections (P less than 0.1) than Lu.lichyi (37%) or Lu.pia (44%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Leishmania infection in humans, dogs and sandflies in a visceral leishmaniasis endemic area in Maranhão, Brazil

Leishmania infection in humans, dogs and sandflies was examined in the endemic visceral leishmaniasis (VL) municipality of Raposa, state of Maranh?o, Brazil. In this study, we examined Leishmania chagasi infection in the blood serum of both humans and Canis familiaris and the natural Leishmania sp. infection rate in the sandfly vector, Lutzomyia longipalpis. Enzyme-linked immunosorbent assay, indirect immunofluorescence reaction and polymerase chain reaction were performed to detect Leishmania infections in humans, dogs and sandflies, respectively. Overall, 186 out of 986 studied human beings were infected with L. chagasi parasites, representing an infection prevalence of 18.9%. An even higher infection rate was detected in dogs, where 66 (47.8%) out of 138 were infected. Among all Lu. longipalpis captured (n = 1,881), only 26.7% were females. The Leishmania infection frequency for the vector Lu. longipalpis was 1.56%. Remarkably, all infected sandflies were found in the peridomiciliary area. Furthermore, a high incidence of asymptomatic forms of VL in the human and canine populations was observed. The results of this study suggest autochthonous transmission of L. chagasi in this endemic area for visceral leishmaniasis because infection by Leishmania sp. was identified in all important elements of the transmission chain.     

Human mixed infections of Leishmania spp. and Leishmania-Trypanosoma cruzi in a sub Andean Bolivian area: identification by polymerase chain reaction/hybridization and isoenzyme

Parasites belonging to Leishmania braziliensis, Leishmania donovani, Leishmania mexicana complexes and Trypanosoma cruzi (clones 20 and 39) were searched in blood, lesions and strains collected from 28 patients with active cutaneous leishmaniasis and one patient with visceral leishmaniasis. PCR-hybridization with specific probes of Leishmania complexes (L. braziliensis, L. donovani and L. mexicana) and T. cruzi clones was applied to the different DNA samples. Over 29 patients, 8 (27.6%) presented a mixed infection Leishmania complex species, 17 (58.6%) a mixed infection Leishmania-T. cruzi, and 4 (13.8%) a multi Leishmania-T. cruzi infection. Several patients were infected by the two Bolivian major clones 20 and 39 of T. cruzi (44.8%). The L. braziliensis complex was more frequently detected in lesions than in blood and a reverse result was observed for L. mexicana complex. The polymerase chain reaction-hybridization design offers new arguments supporting the idea of an underestimated rate of visceral leishmanisis in Bolivia. Parasites were isolated by culture from the blood of two patients and lesions of 10 patients. The UPGMA (unweighted pair-group method with arithmetic averages) dendrogram computed from Jaccard's distances obtained from 11 isoenzyme loci data confirmed the presence of the three Leishmania complexes and undoubtedly identified human infections by L. (V.) braziliensis, L. (L.) chagasi and L. (L.) mexicana species. Additional evidence of parasite mixtures was visualized through mixed isoenzyme profiles, L. (V.) braziliensis-L. (L.) mexicana and Leishmania spp.-T. cruzi.The epidemiological profile in the studied area appeared more complex than currently known. This is the first report of parasitological evidence of Bolivian patients with trypanosomatidae multi infections and consequences on the diseases' control and patient treatments are discussed.     

Leishmaniasis in Bolivia. II. The involvement of Psychodopygus yucumensis and Psychodopygus llanosmartinsi in the selvatic transmission cycle of Leishmania braziliensis braziliensis in a lowland subandean region

An epidemiological survey of the vectors of cutaneous leishmaniasis ("espúndia" type) was carried out in the Alto Beni region of Bolivia, an area of Andean foothills at the Eastern limit of the Amazonian lowlands. The climate is typical wet tropical (15 degrees S latitude). Anthropophilic phlebotomine sandfly species were sampled at 20 sites, all forested. The importance of species from the Psychodopygus group, already suspected as a vector in the transmission of Leishmania from the braziliensis complex, was confirmed by: the aggressiveness and diversity of the species encountered (83% of catches, nine species), the discovery of a new anthropophilic species, P. yucumensis and the isolation of a strain of Leishmania braziliensis braziliensis indistinguishable from human strains from the same area, from two species, P. llanosmartinsi and P. yucumensis.     

Leishmania (Viannia) braziliensis: epidemiology of canine cutaneous leishmaniasis in the State of Paraná (Brazil)

The present study examines the role that dogs play in the maintenance of the Leishmania cycle in the State of Paraná, Southern Brazil. Dogs were examined in three regions where cutaneous leishmaniasis is endemic or epidemic (R1-Vale da Ribeira; R2-Central region of Paraná State and R3-Northern region). To determine serum prevalence rates ELISA was used. In regions endemic for Trypanosoma cruzi (R1 and R3), serum from dogs seroreactive towards Leishmania antigen was subjected to T. cruzi adsorption in order to eliminate cross-reaction with common antigen epitopes. Concomitantly, dogs with cutaneous lesions were biopsied to isolate and identify parasites using RAPD. Leishmania were classified by the phenetic method using the Jaccard coefficient of similarity, and grouped by Unweighted Pair-Group Method using an Arithmetic Average (UPGMA). A total of 410 dogs were studied. In R1 (Vale da Ribeira) 159 dogs were evaluated of which 10 had anti-Leishmania antibody. In R2 (Central Paraná), 39 animals were examined of which 8 were seropositive. In R3 (the North) 212 dogs were evaluated of which 39 animals were seropositive. Thirteen dogs had cutaneous lesions and the parasites were isolated from a dog with mucocutaneous lesion in R1, two animals with simple skin lesions in R2 and 10 dogs with multiple lesions in R3. The identification of the parasite by molecular methods showed it to be L. (Viannia) braziliensis. Based on this information, the role of domestic dogs in Leishmania infection of cutaneous leishmaniasis in Paraná is discussed.     

Leishmania (Viannia) braziliensis: insights on subcellular distribution and biochemical properties of heparin-binding proteins

Leishmaniasis is a vector-borne disease and an important public health issue. Glycosaminoglycan ligands in Leishmania parasites are potential targets for new strategies to control this disease. We report the subcellular distribution of heparin-binding proteins (HBPs) in Leishmania (Viannia) braziliensis and specific biochemical characteristics of L. (V.) braziliensis HBPs. Promastigotes were fractionated, and flagella and membrane samples were applied to HiTrap Heparin affinity chromatography columns. Heparin-bound fractions from flagella and membrane samples were designated HBP Ff and HBP Mf, respectively. Fraction HBP Ff presented a higher concentration of HBPs relative to HBP Mf, and SDS-PAGE analyses showed 2 major protein bands in both fractions (65 and 55 kDa). The 65 kDa band showed gelatinolytic activity and was sensitive to inhibition by 1,10-phenanthroline. The localization of HBPs on the promastigote surfaces was confirmed using surface plasmon resonance (SPR) biosensor analysis by binding the parasites to a heparin-coated sensor chip; that was inhibited in a dose-dependent manner by pre-incubating the parasites with variable concentrations of heparin, thus indicating distinct heparin-binding capacities for the two fractions. In conclusion, protein fractions isolated from either the flagella or membranes of L. (V.) braziliensis promastigotes have characteristics of metallo-proteinases and are able to bind to glycosaminoglycans.     

Vectors of cutaneous leishmaniasis in north-central Venezuela

Abstract. An entomological survey was undertaken from January 1991 to February 1992 in El Ingenio, Miranda State, Venezuela, an endemic area of cutaneous leishmaniasis: prevalence of 10.7 cases per 100,000 inhabitants.
A total of 4863 female sandflies (Phlebotominae) of fourteen species were collected in Shannon traps, then dissected and examined for leishmanial infections.
Lutzomyia ovallesi (85.4%) and Lu. gomezl (11.2%) were the predominant anthropophilic species of sandfly. Fifty-one (1.19%) Lu. ovallesi and two(0.47%) Lu. gomezi had natural infection with Leishmania promastigotes. Identification of the parasites was done by using the polymerase chain reaction (PCR) and DNA hybridization. Two isolates from Lu. gomezi and forty-nine from Lu. ovallesi were typed as Leishmania braziliensis and three of the latter reacted with Le. mexicana also. This is the first report of Lu. gomezi with parasites typed as Le. braziliensis.
We concluded that Lu. ovallesi is the primary vector of cutaneous leishmaniasis in the north-central area of Venezuela and Lu. gomezi should be regarded as an additional vector.     

In vitro antileishmanial and antitrypanosomal activities of flavanones from Baccharis retusa DC. (Asteraceae)

Leishmaniasis and Chagas' are parasitic protozoan diseases that affect the poorest population in the world, causing a high mortality and morbidity. As a result of highly toxic and long-term treatments, novel, safe and more efficacious drugs are essential. In this work, the CH(2)Cl(2) phase from MeOH extract from the leaves of Baccharis retusa DC. (Asteraceae) was fractioned to afford two flavonoids: naringenin (1) and sakuranetin (2). These compounds were in vitro tested against Leishmania spp. promastigotes and amastigotes and Trypanosoma cruzi trypomastigotes and amastigotes. Compound 2 presented activity against Leishmania (L.) amazonensis, Leishmania (V.) braziliensis, Leishmania (L.) major, and Leishmania (L.) chagasi with IC(50) values in the range between 43 and 52 μg/mL and against T. cruzi trypomastigotes (IC(50)=20.17 μg/mL). Despite of the chemical similarity, compound 1 did not show antiparasitic activity. Additionally, compound 2 was subjected to a methylation procedure to give sakuranetin-4'-methyl ether (3), which resulted in an inactive compound against both Leishmania spp. and T. cruzi. The obtained results indicated that the presence of one hydroxyl group at C-4' associated to one methoxyl group at C-7 is important to the antiparasitic activity. Further drug design studies aiming derivatives could be a promising tool for the development of new therapeutic agents for Leishmaniasis and Chagas' disease.     

Experimental canine mucocutaneous leishmaniasis (Leishmania braziliensis braziliensis)

Four mongrel dogs were intradermically inoculated with 3 x 10(6) Leishmania braziliensis braziliensis promastigotes. Three out of the four animals developed cutaneous lesions respectively 4, 7, and 8 months after. The fourth dog did not develop lesion at the inoculation site, but a mucosal ulcer was seen 16 months after the inoculum. Clinical, histopathological, and serological findings were similar to what is found in natural canine infection as well as in the human disease. These results suggest that dogs may be an useful model for L. b. braziliensis infection.     

Transmission of Leishmania donovani in the Hills of Eastern Nepal,an Outbreak Investigation in Okhaldhunga and Bhojpur Districts

Background

In the Indian subcontinent, Visceral leishmaniasis is endemic in a geographical area coinciding with the Lower Gangetic Plain, at low altitude. VL occurring in residents of hill districts is therefore often considered the result of Leishmania donovani infection during travel. Early 2014 we conducted an outbreak investigation in Okhaldhunga and Bhojpur districts in the Nepal hills where increasing number of VL cases have been reported.

Methodology/Principal Findings

A house-to-house survey in six villages documented retrospectively 35 cases of Visceral Leishmaniasis (VL). Anti-Leishmania antibodies were found in 22/23 past-VL cases, in 40/416 (9.6%) persons without VL and in 12/155 (7.7%) domestic animals. An age- and sex- matched case-control study showed that exposure to known VL-endemic regions was no risk factor for VL, but having a VL case in the neighbourhood was. SSU-rDNA PCR for Leishmania sp. was positive in 24 (5%) of the human, in 18 (12%) of the animal samples and in 16 (14%) bloodfed female Phlebotomus argentipes sand flies. L. donovani was confirmed in two asymptomatic individuals and in one sand fly through hsp70-based sequencing.

Conclusions/Significance

This is epidemiological and entomological evidence for ongoing local transmission of L. donovani in villages at an altitude above 600 meters in Nepal, in districts considered hitherto non-endemic for VL. The VL Elimination Initiative in Nepal should therefore consider extending its surveillance and control activities in order to assure VL elimination, and the risk map for VL should be redesigned.     

Epidemiological characteristics of American cutaneous leishmaniasis in an endemic region of the State of Bahia. III. Phlebotomine fauna

The phlebotomine fauna is highly varied in Três Bra?os, an endemic area of american cutaneous leishmaniasis, situated in the cacao growing region in the southeast of Bahia State, Brazil. Thirty spécies of the Lutzomyia genus were identified in 13,535 specimens collected between 1976 and 1984. Lutzomyia whitmani was the dominant species accounting for 99% of flies in the peridomicile and 97.5% of those caught in homes. In the forest the predominant species were Lu. ayrozai and Lu. yuilli. Lu. whitmani accounted for only 1.0% of the specimens examined. Lu. flaviscutellata, the proven vector of Leishmania mexicana amazonensis, was also collected in small numbers. Lu. wellcomei, a known vector of L. braziliensis braziliensis in the Serra dos Carajás, Pará, Brazil was not encountered in the Três Bra?os region where the parasite causing human infections is usually L.b. braziliensis. Although we have not encountered a natural infection with leishmanial promastigotes in 1,832 females of the various species examined, we discuss the probability that Lu. whitmani is the vector of L.b. braziliensis in the region maintaining transmission in dogs and man.