Gustavo Fontes Paz

Epidemiological aspects of human and canine visceral leishmaniasis in Montes Claros, State of Minas Gerais, Brazil, between 2007 and 2009

INTRODUCTION Visceral leishmaniasis (VL) is an expanding zoonosis in Brazil and is becoming urbanized in several Brazilian regions. This study aims to describe the epidemiological features of human and canine VL in the municipality of Montes Claros, State of Minas Gerais, by focusing on their spatial distribution. METHODS Data concerning human cases and reactive dogs for VL from 2007 to 2009 were obtained from the Information System for Disease Notification (SINAN) and from reports of the local Centro de Controle de Zoonoses (CCZ), respectively. The addresses of human and canine cases have been georeferenced and localized in thematic maps, allowing their spatial visualization as well as the identification of areas at risk of VL transmission. RESULTS Ninety-five cases of human VL were reported in the period. The 0-9-year-old age group (48.4%) was the most affected, within which the majority consisted of male patients (64%). Of the samples collected for the canine serological survey, 2,919 (6.3%) were reactive to VL. The spatial localization of these cases shows that the disease was scattered in the urban area of the municipality. Areas showing a higher dissemination risk were concentrated in the central, northwestern, and southern regions of the city. CONCLUSIONS Identifying the areas most at risk in urban Montes Claros may help guide actions toward local epidemiological vigilance and control.

Eco-epidemiology of visceral leishmaniasis in the urban area of Paracatu, state of Minas Gerais, Brazil.

The present study was developed in the urban area of Paracatu, an endemic city for the American visceral leishmaniasis in Brazil. A six-month canine survey was performed with 6295 domiciled dogs in 28 districts in that area and showed that 4.2% of those (267 dogs) were positive for VL by ELISA and IFAT serum assays. Prevalence ratios for canine VL varied between 1.2% and 16.1%, depending on the district under investigation. Fifteen dogs - 80% of which were clinically asymptomatic for VL - were submitted to a more detailed study that comprised direct parasitological examination and Leishmania kDNA amplification of tissue samples as well as two PCR-RFLP methods using myelocultures. Leishmania amastigotes or Leishmania DNA were detected in all dogs but one. The infecting species of Leishmania was identified in about 50% (7/15) of the sample dogs: Leishmania (Leishmania) chagasi in two of them and, unexpectedly, Leishmania (Leishmania) amazonensis in the remaining five. Three months after the end of confiscation and elimination of the VL-seropositive dogs in the 28 districts of Paracatu, a systematic entomological survey was performed in five of them. Six hundred and sixty five (665) phlebotomine sand flies were captured in total, from which 89.5% were identified as Lutzomyia longipalpis. The population density of that species increased during the rainy season. Other thirteen (13) species of phlebotomine sand flies were captured at varying percentages from 0.2 to 5.0%. It is worth noting that L. longipalpis females were predominantely intradomicile when compared to males, suggesting that the VL transmission cycle in Paracatu may be occurring inside home.

Association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti-Leishmania antibodies: A case–control study in dogs from a Brazilian endemic area

The association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti-Leishmania antibodies has been evaluated in dogs located in a city of Brazil endemic for canine visceral leishmaniasis. Blood samples from 5556 domestic dogs domiciliated in the urban area of Belo Horizonte (Minas Gerais state) were submitted to enzyme linked immunosorbent (ELISA) and indirect immunofluorescent antibody (IFAT) assays, and 432 (7.8%) animals tested positive. Seropositive (n=200) and seronegative (n=200) dogs were randomly selected and examined for the presence of ticks and fleas, the results of which were expressed qualitatively as infested or non-infested, irrespective of the intensity of infestation. The prevalence of infestation by R. sanguineus was significantly greater (ρ=0.04) among seropositive dogs (38.5%) compared with their seronegative counterparts (29.0%). Similarly, the prevalence of infestation by C. felis felis was significantly greater (ρ<0.01) within the seropositive group (36.5%) than within the seronegative group (15.0%). Moreover, the probability of seropositivity for Leishmania was 53% higher in tick-infested dogs and 300% higher in flea-infested dogs in comparison with non-infested animals. Our data provide evidence of the vectorial capacity of these ectoparasites in transmitting Leishmania to the canine population, although further studies are needed to confirm or reject this hypothesis.

Ritmo de queda de Rhipicephalus sanguineus (Acari: Ixodidae) de cães artificialmente infestados

The present study evaluated the drop-off rhythm of Rhipicephalus sanguineus (Latreille) ticks from two populations from Brazil, one from Monte Negro, state of Rondonia, and another from Belo Horizonte, state of Minas Gerais. Artificial infestations with ticks were performed on dogs in the laboratory, held in a light: scotophase regimen of 12:12 h. Larval drop-off rhythm was characterized by similar number of engorged larvae detaching during both periods of light and scotophase, or by a larger number of larvae detaching during the light period. In contrast, most of the engorged nymphs and females detached from dogs during the scotophase period. These results indicate that under natural conditions, most of R. sanguineus engorged nymphs and females detach from dogs during the night period, whereas engorged larvae detach in higher proportions during daytime. Based on these data, tick control measures, encompassing environmental treatments with acaricide, should be indicated. The control measures are especially indicated in places where dogs spend or visit during the night period, since these places possibly harbor most of the free-living stages of R. sanguineus.

Evaluation of the vectorial capacity of Rhipicephalus sanguineus (Acari: Ixodidae) in the transmission of canine visceral leishmaniasis.

The vectorial capacity of Rhipicephalus sanguineus in the transmission of canine visceral leishmaniasis has been evaluated through a laboratory-controlled experiment. One healthy Leishmania-free dog and two dogs naturally infected with Leishmania were infested with R. sanguineus in various stages of development. Engorged larvae, unfed nymphs, engorged nymphs, unfed adults, engorged female adults and fed male adults were collected from the experimental animals and examined for Leishmania infection by optical microscopy, polymerase chain reaction (PCR) and parasite culture. Leishmania forms were not detected in any of the 433 smears prepared from engorged colonies nor in any of the 118 smears prepared from unfed colonies. However, one flagellate structure was identified in one of the smears. All pools of R. sanguineus that had fed on the infected dogs tested PCR-positive for Leishmania DNA, with the single exception of the pool of engorged larvae. In contrast, all pools of ticks that had fed on the Leishmania-free dog were PCR-negative. Leishmania growth was not observed in any of the tick colonies following incubation on culture medium. Considering that no Leishmania forms were identified in any of the meticulously analysed smears derived from engorged colonies of R. sanguineus, it appears somewhat unlikely that the maintenance and multiplication of Leishmania occurs within the tick.

Phlebotomine sandflies (Diptera: Psychodidae) in Governador Valadares, a transmission area for American tegumentary leishmaniasis in State of Minas Gerais, Brazil

INTRODUCTION A study on the phlebotomine sandfly fauna was carried out in an endemic area for American tegumentary leishmaniasis in the municipality of Governador Valadares, in the State of Minas Gerais, Brazil. METHODS Captures were undertaken using HP light traps in four districts, on three nights per month, for one year (from January to December 2008). Correlations between climatic factors (temperature, relative air humidity and rainfall) and the numbers of sandflies collected was observed. RESULTS 5,413 phlebotomine specimens were caught and were identified as belonging to 12 species. Of these specimens, 2,851 (52%) were females and 2,562 (48%) were males. CONCLUSIONS Lutzomyia intermedia predominated (29.9% of the species caught), thus suggesting that they were responsible for transmission of American tegumentary leishmaniasis, together with L. whitmani, which was also found in the area (4.3%). The presence of L. longipalpis (11.9%), the main vector for visceral leishmaniasis in Brazil, is an important finding, which makes rigorous entomological surveillance of the area necessary.

Associação entre sorologia para Neospora caninum e taxa de prenhez em vacas receptoras de embriões

The association between seropositivity for Neospora caninum and pregnancy rate in cows belonging to a surrogate herd submitted to embryo transfer technology was determined. The serological status was evaluated in 275 heifers, aging from 14 to 20-month-old. For N. caninum serology analysis of a monoclonal competitive ELISA test Kit was used, and 81 animals (29.5%) showed seropositive. Thus, two groups were randomly formed selecting 33 seropositive heifers and other 33 seronegative animals out of the remaining 194 animals. Seronegative animals were followed up by serological analysis until the end of the trial in order to identify persistently infected individuals. The pregnancy rate was 72.7% in the group of N. caninum-positive sera, and, 81.8% in the seronegative group.No significant difference was observed between groups according to Chi-square test. No association between N. caninum seropositivity and pregnancy rates in surrogate heifers was found.

Controle de Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) no canil da Escola de Veterinária da UFMG, Belo Horizonte, Minas Gerais, Brasil

2 ABSTRACT:- PAZ, G.F.; LEITE, R.C.; OLIVEIRA, P.R. DE. (Control of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) in the kennel of the UFMG Veterinary School, Belo Horizonte, Minas Gerais, Brazil). Controle de Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) no canil da Escola de Veterinaria da UFMG, Belo Horizonte, Minas Gerais, Brasil. Revista Brasileira de Parasitologia Veterinaria, v. 17, n. 1, p.41-44, 2008. Escola de Veterinaria, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901. E-mail: rcleite@vet.ufmg.br The present work was aimed at proposing a control measure for Rhipicephalus sanguineus in a naturally infected kennel of 72 m 2 of the UFMG Veterinary School with 25 dogs of different breeds. A sensitivity test to acaricide products was applied in a sample of R. sanguineus. Out of the acaricide products tested: 12.5% Amitraz (product 1); 2% Alfamethrin and 60% Dichlorvos association (product 2); 5% Deltamethrin (product 3) and the association between 77.6% Trichlorfon, 1.0% Coumaphos and 1.0% Cyfluthrin (product 4); only 1 and 4 products showed 100% efficacy. Amitraz (12.5%) was used for controlling R. sanguineus in the surrounding of the kennel, on which four treatments every seven days were carried out in the facilities. For parasitic R. sanguineus, a single topical treatment was used: Flumetrin 1.0% pour - on on all the 25 dogs. This control measure significantly reduced the population of R. sanguineus within the kennel. A slight infestation was observed in the seventh month after treatment. A new application of 12.5% Amitraz was done in the kennel as well as a new topical treatment with Flumetrin 1.0% pour - on on the dogs. The control procedure proposed in the present study was an emergency measure and its effectiveness was checked through environmental surveys throughout a one-year period.

Leishmania, Babesia and Ehrlichia in urban pet dogs: co-infection or cross-reaction in serological methods?

INTRODUCTION The present study was designed to assess the occurrence of co-infection or cross-reaction in the serological techniques used for detecting the anti-Leishmania spp., -Babesia canis vogeli and -Ehrlichia canis antibodies in urban dogs from an area endemic to these parasites. METHODS The serum samples from dogs were tested for the Babesia canis vogeli strain Belo Horizonte antigen and Ehrlichia canis strain São Paulo by immunofluorescence antibody test (IFAT) and by anti-Leishmania immunoglobulin G (IgG) antibody detection to assess Leishmania infection. We used the following four commercial kits for canine visceral leishmaniasis: ELISA, IFAT, Dual Path Platform (DPP) (Bio Manguinhos(r)/FIOCRUZ/MS) and a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios). RESULTS Of 96 serum samples submitted to serological assays, 4 (4.2%) were positive for Leishmania as determined by ELISA; 12 (12.5%), by IFAT; 14 (14.6%) by rK39 RDT; and 20 (20.8%), by DPP. Antibodies against Ehrlichia and Babesia were detected in 23/96 (23.9%) and 30/96 (31.2%) samples, respectively. No significant association was identified between the results of tests for detecting Babesia or Ehrlichia and those for detecting Leishmania (p-value>0.05). CONCLUSIONS In the present study, we demonstrated co-infection with Ehrlichia or Babesia and Leishmania in dogs from Minas Gerais (Brazil); we also found that the serological tests that were used did not cross-react.

Ectoparasites and anti-Leishmania antibodies: Association in an observational case–control study of dogs from a Brazilian endemic area

It has been proposed that the transmission of canine visceral leishmaniasis might involve the participation of mechanical vectors, including ticks of the family Ixodidae, in particular the brown dog tick Rhipicephalus sanguineus, and the cat flea Ctenocephalides felis felis. Here, the association between the infestation by R. sanguineus and C. felis felis and the occurrence of anti-Leishmania antibodies was evaluated in an observational case-control study of dogs living in a Brazilian endemic area for canine visceral leishmaniasis. Blood samples were taken once every three months for one year from 96 initially seronegative domestic dogs, and submitted to indirect immunofluorescence antibody assay. All dogs were evaluated for the presence of ticks and fleas, and the results were expressed qualitatively as infested or non-infested, irrespective of the intensity of infestation. At the end of follow-up, twenty dogs had turned seropositive, while 68 remained seronegative and 8 were excluded because of incomplete data. All the dogs were asymptomatic. The odds of infection was significantly greater (OR=3.54, CI95%=1.10-12.53) for dogs infested by C. felis felis compared to their non-infested counterparts. In contrast, the odds of infection showed no significance difference between non-infested and R. sanguineus-infested groups of dogs (OR=0.31, CI95%=0.03-1.52). This study provides further evidence for the potential role of C. felis felis in mechanically transmitting Leishmania among the canine population.