Isolation of Leishmania from monkeys in the Amazon Region of Brazil

Parasites of Free-Ranging and Captive American Primates: A Systematic Review

The diversity, spread, and evolution of parasites in non-human primates (NHPs) is a relevant issue for human public health as well as for NHPs conservation. Although previous reviews have recorded information on parasites in NHPs (Platyrrhines) in the Americas, the increasing number of recent studies has made these inventories far from complete. Here, we summarize information about parasites recently reported in Platyrrhines, attempting to build on earlier reviews and identify information gaps. A systematic literature search was conducted in PubMed, ISI Web of Science, and Latin American and Caribbean Health Sciences Literature (LILACS), and following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Ninety-three studies were included after the screening process. Records for 20 genera of NHPs, including 90 species were found. Most of the studies were conducted on captive individuals (54.1%), and morphological approaches were the most used for parasite identification. The most commonly collected biological samples were blood and stool, and Protozoa was the most frequent parasite group found. There is still scarce (if any) information on the parasites associated to several Platyrrhine species, especially for free-ranging populations. The use of molecular identification methods can provide important contributions to the field of NHPs parasitology in the near future. Finally, the identification of parasites in NHPs populations will continue to provide relevant information in the context of pervasive habitat loss and fragmentation that should influence both human public health and wildlife conservation strategies.

Ecology of phlebotomine sand flies in a Brazilian area with recent leishmaniasis transmission (Itaúna, in Minas Gerais state)

INTRODUCTION:

Leishmaniasis constitutes a serious but neglected tropical disease. Recently, socio-environmental, biological and physical changes have altered the range of leishmaniasis, causing it to spread into urban areas. In Minas Gerais, the disease is endemic, exhibiting regional differences and reaching urban centers. The purpose of this study was to evaluate entomological aspects related to the ecoepidemiology of leishmaniasis in Itaúna.

METHODS:

Monthly catches with HP traps were carried out from June 2017 to May 2018, in three ecological areas (urban, rural, and forest). The adaptability of the species to anthropic environments was assessed using the synanthropy index (SI).

RESULTS:

We collected 1306 specimens of phlebotomine sand flies. Of the species of medical importance, Lutzomyia longipalpis, the vector of Leishmania infantum, represented 90.4% of the specimens identified at species level (n=1260). Nyssomyia whitmani, the vector of Leishmania braziliensis, represented 1.6% of the total. Lu. longipalpis displayed an SI of +95.8, a value that denotes a marked preference for human environments. For Ny. whitmani, the SI was -25, expressing the tendency of this species to occupy uninhabited areas. The population of the three most numerous species captured increased with rain, high temperatures, and high relative humidity. Although captured at low numbers, Ny. whitmani showed a different profile concerning the climate variables analyzed.

CONCLUSIONS:

Understanding the epidemiology of the disease may assist the health services in formulating effective control measures for improving community health and contributing to the establishment of a dynamic relationship and a global awareness of the health/disease process.

Leishmaniasis in non-human primates: Clinical and pathological manifestations and potential as reservoirs

Although the domestic dog is the most important reservoir of visceral leishmaniasis in urban areas, there have been an increasing number of reports of naturally occurring leishmaniasis in non-human primates. Reported cases affecting neotropical and Old World non-human primates as well as their potential role as reservoirs were reviewed.

First report of Leishmania infantum infection in the endangered orangutan (Pongo pygmaeus pygmaeus) in Madrid, Spain

Background

Some wild animals have been recognized as potential reservoirs of Leishmania infantum infection (e.g. carnivores, lagomorphs, rodents, etc.). Leishmania infantum was also identified infecting humans and lagomorphs (i.e. hares and rabbits) over the period of 2009–2016, with the latter acting as the main reservoirs involved in the human leishmaniosis outbreak in Madrid.

Results

Two cases of clinical leishmaniosis are reported in orangutans (Pongo pygmaeus pygmaeus) housed at two different centres in Madrid. The first is the case of a 36-year-old male orangutan with severe weight loss and apathy. A complete blood count and biochemical profile revealed anaemia, neutropenia, hypoalbuminaemia and elevated transaminases. Hepato-splenomegaly was also observed. Four months later, due to worsening of clinical signs (mainly bilateral epistaxis), blood and bone marrow samples were collected. Amastigotes of L. infantum were detected in macrophages from a bone marrow aspirate and by specific polymerase chain reaction. The second case was a 34-year-old female orangutan with severe weight loss and apathy and no other apparent clinical signs. A complete blood count and biochemical profile revealed anaemia, pancytopenia and hypoalbuminaemia. Splenomegaly and pericardial effusion were also observed. As leishmaniosis was included in the differential diagnosis, both blood and bone marrow samples were collected. Leishmania infantum infection was confirmed by microscopy, molecular diagnosis and serology (immunofluorescence antibody test). Both animals were treated daily with oral miltefosine for 28 days; allopurinol was also given uninterruptedly in Case 2 for at least 6 months. During follow-up, though good clinical recovery was clear, a lack of parasitological cure was confirmed molecularly in both blood and bone marrow samples from the two orangutans. In both habitats, the presence of the sand fly vector identified as Phlebotomus perniciosus was confirmed.

Conclusions

To our knowledge, this is the first report of L. infantum infection in great apes and in the endangered species P. p. pygmaeus. We are presently looking for L. infantum in other non-human primates living in the same peri-urban areas. If detected, we will examine the impacts of this serious disease on these critically endangered species.

Naturally acquired visceral leishmaniasis in non-human primates in Brazil

Visceral leishmaniasis (VL) is a chronic and often fatal protozoal disease that is endemic in Belo Horizonte (State of Minas Gerais, Brazil). Leishmania sp. is an intracellular obligatory parasite of macrophages that can naturally infect several mammalian species. Non-human primates (NHP) have been used as experimental models for infection with Leishmania of the donovani complex. The present report describes a case of visceral leishmaniasis in a black-fronted titi. Among 41 primates kept in captivity in a zoo in Belo Horizonte (State of Minas Gerais, Brazil), one animal, a black-fronted titi (Callicebus nigrifrons), was positive for Leishmania chagasi infection by PCR and immunohistochemistry, and developed a fatal disease with clinical signs and lesions compatible with VL. Other 17 NHP, including six black-fronted titis (C. nigrifrons), one howler monkey (Alouatta guariba), three golden-bellied capuchins (Cebus xanthosternos), one golden-headed lion tamarin (Leontopithecus crysomelas), one black-headed owl monkey (Aotus nigriceps), two Rio Tapajós sakis (Pithecia irrorata) and three emperor tamarins (Saguinus imperator) had blood samples that tested positive for amplification of Leishmania kDNA by PCR, although these NPH had no clinical signs of the disease.

The utility of rhesus monkey (Macaca mulatta) and other non-human primate models for preclinical testing of Leishmania candidate vaccines

Leishmaniasis causes significant morbidity and mortality, constituting an important global health problem for which there are few effective drugs. Given the urgent need to identify a safe and effective Leishmania vaccine to help prevent the two million new cases of human leishmaniasis worldwide each year, all reasonable efforts to achieve this goal should be made. This includes the use of animal models that are as close to leishmanial infection in humans as is practical and feasible. Old world monkey species (macaques, baboons, mandrills etc.) have the closest evolutionary relatedness to humans among the approachable animal models. The Asian rhesus macaques (Macaca mulatta) are quite susceptible to leishmanial infection, develop a human-like disease, exhibit antibodies to Leishmania and parasite-specific T-cell mediated immune responses both in vivo and in vitro, and can be protected effectively by vaccination. Results from macaque vaccine studies could also prove useful in guiding the design of human vaccine trials. This review summarizes our current knowledge on this topic and proposes potential approaches that may result in the more effective use of the macaque model to maximize its potential to help the development of an effective vaccine for human leishmaniasis.

[Experimental skin leishmaniasis: II--course of the infection in the Cebus apella primate (Cebidae) caused by Leishmania (V.) braziliensis and L. (L.) amazonensis]

As a means of assessing the usefulness of the monkey Cebus apella as an experimental model for the study of cutaneous leishmaniasis, 5 of these animals were inoculated intradermally at 8 sites along the tail with 3 X 10(6) promastigotes of L. (V.) braziliensis, while a further 5 monkeys received similar inoculations with 3 X 10(6) promastigotes of L. (L.) amazonensis. Following the inoculations, weekly examinations and monthly biopsies showed evolution of resulting skin lesions to be as follows: a) L. (V.) braziliensis: lesions were first visible 15-20 days post-inoculation (p.i), and at 30 days they were clearly of an erythematous-papular nature, which assumed a nodular form at 60 days; after 3 months a spontaneous ulceration of these lesions was noted and, at 4 months, the initiation of healing. In one animal total healing was apparent 5 months p.i; in two others at 6 months, in another monkey after 7 months, and in the last animal at 10 months p.i. Amastigotes were demonstrated in smears from the lesions of all monkeys up to 90 days p.i; up to 120 days in two animals, and at 180 days p.i. in the monkey which showed resolution of the lesions after 10 months. b) L. (L.) amazonensis lesions were first apparent after 20 days p.i; at 30 days they were of an erythematous-papular nature, developing into nodules at 60 days. From the third month of infection onwards, however, the lesions diminished rapidly and, at 90 days p.i. amastigotes were no longer detectable in the skin.(ABSTRACT TRUNCATED AT 250 WORDS)

[Experimental cutaneous leishmaniasis: I--on the susceptibility of the primate Cebus apella (Cebidae) to the infection caused by Leishmania (Viannia) lainsoni Silveira, Shaw and Ishikawa, 1987]

The susceptibility of the monkey Cebus apella (Cebidae) to experimental infection by Leishmania (Viannia) lainsoni has been investigated. For this purpose, five young monkeys, 2 males and 3 females, were intradermally, inoculated, in eight different places along the dorsal surface of the tail with 3 x 10(6) promastigotes of the parasite (MHOM/BR/81/M6426, Benevides, Pará), from stationary phase culture in Difco B45 medium. After inoculations, infection in the monkeys was indicated by the presence of amastigotes in the skin lesions produced in these animals at the points of inoculation, confirming the susceptibility of the monkey Cebus apella to experimental infection by Leishmania lainsoni, with an infection period of four months. This represents a suitable period for testing antileishmanial drugs or studying the pathogenesis of the disease caused by this parasite.