Antibacterial effects of the lectin from pomegranate sarcotesta (PgTeL) against Listeria monocytogenes

AIMS

To investigate the effects of the lectin from Punica granatum sarcotesta (PgTeL) on growth, viability, cell structure, biofilm formation and chitinase activity of Listeria monocytogenes. In addition, the effect of PgTeL on the adhesion and invasion of human cells (HeLa) was determined.

METHODS AND RESULTS

PgTeL showed bacteriostatic and bactericidal effects on the strains L. monocytogenes N53-1 and EGD-e, causing morphometric alterations, cell aggregation, strong deformation and cell disruption. PgTeL inhibited biofilm formation by EGD-e and N53-1 and also interfered with the adhesion and invasion processes of EGD-e and N53-1 in HeLa cells. Finally, the chitinase activity of L. monocytogenes EGD-e was reduced in the presence of PgTeL, which can be involved in the inhibition of adhesion process.

CONCLUSION

PgTeL is an antibacterial agent against L. monocytogenes, inhibiting growth and promoting cell death, as well as impairing biofilm formation and bacterial adhesion and invasion into human cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results stimulate future investigations on the potential of PgTeL for protection of contamination in food products.

Occurrence of zoonotic gastrointestinal parasites of rodents and the risk of human infection in different biomes of Brazil

Rodents are synanthropic mammals adapted to several ecosystems, where they can contribute to the transmission of zoonotic pathogens, including gastrointestinal parasites. The aim of this study was to study the occurrence of gastrointestinal parasites from rodents and discuss the risk of transmission to humans. Fecal samples (n = 110) from different rodent species, namely, Cerradomys subflavus (n = 4), Mus musculus (n = 14), Rattus norvegicus (n = 80), Rattus rattus (n = 8) and Thrichomys apereoides (n = 4), were analyzed using the FLOTAC technique. Of the samples examined, 73.6% (81/110) tested positive for at least one gastrointestinal parasite. The most commonly identified parasites were Aspiculuris sp., Hymenolepis nana, Moniliformis sp., Syphacia sp., Strongyloides spp., Taenia spp., and Trichuris spp. eggs, Angiostrongylus cantonensis larvae and Entamoeba spp. cysts. The findings of this study demonstrate that rodents living in different Brazilian biomes are parasitized by a wide range of parasites, including some of public health concern. Therefore, the proximity of rodents to human settlements may represent a tangible risk of infection for people living in these areas.

Zoonotic parasites in wild animals such as carnivores and primates that are traded illegally in Brazil

Brazil accounts for around 20% of all animal species, but these are constantly threatened by illegal anthropic activities. Unfortunately, animal dealers are totally unaware of the sanitary risks among wild animals, or that occurrences of parasites in these animals are bioindicators for their current sanitary status within the ecosystem in which they live. This status is an important parameter with regard to assessing the spreading of pathogens. Therefore, the aim of this study was to perform a survey of zoonotic parasites in carnivores and non-human primates that are illegally traded in Brazil. Between June 2016 and July 2017, 43 wild animals (20 carnivores and 23 non-human primates) were presented at the Wild Animal Screening Center of Sergipe (CETAS/SE). Fecal and blood samples were obtained and analyzed to detect occurrences of pathogens of medical and veterinary importance, such as Cryptosporidium spp., Giardia spp., Dirofilaria immitis, Leishmania infantum, Leishmania braziliensis, Toxoplasma gondii, Trypanosoma cruzi and gastrointestinal helminths. Out of all the animals analyzed, 55.8% (24/43) were found to be positive for at least one parasite species, i.e. 41.7% and 58.3% of the carnivores and non-human primates, respectively. However, all the animals were negative for D. immitis, L. braziliensis and T. cruzi. These findings demonstrate that illegally traded wild animals may represent a risk to public health because of absence of sanitary control during their transportation. Therefore, preventive measures might be employed to avoid infection of these animals and people in close contact with them.

Prevalence and risk factors associated with infection by Eimeria spp. in goats and sheep in Northeastern Brazil

Eimeria spp. infections lead to acute or chronic intestinal disorders in small ruminants, being responsible for important economic losses worldwide. The aim of this study was to assess the risk factors associated with Eimeria spp. infection in small ruminants of the microregion of Garanhuns, state of Pernambuco, Northeastern Brazil. Fecal samples (n = 822) were obtained from goats (n = 414) and sheep (n = 408) and evaluated by the modified Gordon and Whitlock technique. Risk factors were assessed through univariate analysis and logistical regression. Oocysts of Eimeria species were detected in 62.9% (517/822) of the animals, with 77.8% (322/414) in goats and 47.8% (195/408) in sheep. For goats, the herd size (OR = 5.52), rearing system (OR = 1.57), feeding place (OR = 2.60), absence of mineral salt in the diet (OR = 2.54), flooring type (OR = 2.83) and periodicity of cleaning (OR = 5.39) were considered risk factors. Conversely, for sheep only the herd size (OR = 3.16) and rearing system (OR = 2.45) were important factors associated with infection by Eimeria spp. Data herein obtained brings meaningful information on the epidemiology of coccidiosis in small ruminants in Northeastern Brazil. The knowledge of these risk factors is useful to contribute to the development of preventive measures, thereby, reducing the economic impact caused by these protozoa in small ruminant production.

Detection of Rickettsia felis in ectoparasites collected from domestic animals

Ticks and fleas are arthropods widely distributed around the world involved in the transmission of various vector-borne diseases (VBDs), including Brazilian Spotted Fever (BSF), Baggio-Yoshinari Syndrome and the plague, with outstanding consequences for the public health. The aim of this study was to investigate the presence of Rickettsia spp., Borrelia spp. and Yersinia pestis in arthropods collected from dogs, cats and horses living in the state of Pernambuco, Northeastern Brazil. From January 2017 to April 2019, ectoparasites were collected, morphologically identified and molecularly analysed through PCR and sequencing. In total 401 specimens were collected from 86 animals, being 68% (n = 273) and 32% (n = 128) from rural and urban areas, respectively. The most commonly detected species were the ticks Dermacentor nitens, Amblyomma sculptum, Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus microplus, and Amblyomma ovale, and the fleas Ctenocephalides felis and Ctenocephalides canis. DNA of Rickettsia felis was detected in D. nitens collected from horses, and C. felis, and R. sanguineus s.l. collected from dogs. All samples scored negative for Borrelia spp. and Y. pestis DNA. This study provides valuable data on ectoparasite fauna from domestic animals and identifies the circulation of a zoonotic pathogen (i.e., R. felis) in the population of the arthropods assessed. Therefore, preventive measures should be adopted in order to reduce the risk of occurrence of neglected VBD caused by this pathogen in animal and human hosts.

Sandflies in an endemic area for Visceral Leishmaniasis in Northeastern Brazil

Abstract Phlebotomines of the genus Lutzomyia are important vector for species of Leishmania, the etiological agent of leishmaniasis. The aim of this study was to assess the diversity of sandflies in an endemic area for Visceral Leishmaniasis (VL). Sampling was performed in four localities on the coast of the municipality of Goiana, state of Pernambuco, Northeastern Brazil. Specimens were collected monthly on three consecutive nights, from November 2017 to October 2018. CDC light traps were installed at a height of 1.5 m above the ground, in two ecotypes (i.e. tree and animal facility), both in peridomestic areas. A total of 5,205 sandflies were collected, among which the species Lutzomyia longipalpis (99.85%; 5,197/5,205) was the most common, followed by Lutzomyia evandroi (0.13%; 07/5,205) and Lutzomyia whitmani (0.02%; 01/5,205). Specimens of L. longipalpis were collected throughout the study period and most of them were found near to the animal facilities. The findings from this research indicate that vectors for Leishmania infantum are present in the study area throughout the year, along with occurrences of vectors relating to Cutaneous Leishmaniasis (CL). Preventive vector control measures need to be implemented in Goiana to reduce the risk of infection for the human and animal populations.

In vivo effect of essential oil of Mentha x villosa and its active compound against Schistosoma mansoni (Sambon, 1907)

Schistosomiasis treatment is dependent on a single drug, praziquantel (PZQ). The development of resistance of PZQ has drawn the attention of many researchers to alternative drugs. One viable and promising treatment is the study of medicinal plants as a new approach to the experimental treatment for Schistosomiasis. The present work aimed to evaluate in vivo antischistosomal activity of effect of Mentha x villosa Oil Essential (Mv-EO) and rotundifolone (ROT) against Schistosoma mansoni. Thirty-day-old female Swiss webster mice (Mus musculus) weighing 50 grams were used. Mice were infected with 80 cercariae of S. mansoni (BH strain) and orally administered Mv-EO (50, 100 and 200 mg/Kg) and ROT (35.9, 70.9 and 141.9 mg/Kg) at 45-days post infection for 5 consecutive days. All mice were euthanized 60 days after infection. Praziquantel was the positive control in the experiment. Doses of 200 mg/kg (Mv-EO) and ROT (141.9 mg/Kg) resulted in a significant reduction in fluke burden (72.44% and 74.48%, respectively). There was also marked reduction in liver, intestinal and faecal and changed oogram pattern, compared to infected untreated mice. Considering the results obtained, further biological studies are required in order to elucidate the mechanism of schistosomicidal action on against adult S. mansoni.

Spatial distribution of Aedes aegypti (Diptera: Culicidae) in vulnerable areas for the transmission of arboviruses

INTRODUCTION

Areas at risk of transmission of arboviruses have been monitored using ovitraps. This study aimed to evaluate the spatial distribution of Aedes aegypti in vulnerable areas for the transmission of arboviruses and assess the influence of climatic conditions on the infestation of these culicids.

METHODS

Ovitraps were installed in Agrestina, Pernambuco, Northeastern Brazil.

RESULTS

Overall, 44,936 eggs were collected, and the indexes of infestation varied. Relative humidity was significantly associated with the infestations.

CONCLUSIONS

Using ovitraps, entomologic indexes and analysis of climatic factors might be good strategies for monitoring vulnerable areas for the transmission of arboviruses.

An Additional Asset for the FLOTAC Technique: Detection of Gastrointestinal Parasites in Vegetables

INTRODUCTION

Gastrointestinal parasites are considered amongst the most important threats to veterinary and human health worldwide. The transmission of these parasitic diseases usually involves the accidental ingestion of oocysts, cysts, eggs, and larvae, whose detection is generally achieved by classical coproparasitological methods, based on sedimentation and/or flotation techniques. These procedures might be inefficient or display a low sensitivity when performed on food matrices. This study aimed to assess the value of the FLOTAC technique for the detection of different parasitic stages of gastrointestinal parasites of domestic animals in fresh lettuce.

MATERIAL AND METHODS

Samples (n = 100) were purchased from public markets located in the metropolitan region of Recife (Brazil).

RESULTS

A total of 79% scored positive for eggs and/or cysts of gastrointestinal parasites. Protozoa and nematodes were detected in 32% (32/100) and 64% (64/100) of samples, respectively, with cysts of the genus Entamoeba (32%) and eggs of nematodes of the order Strongylida (30%) being the most frequently diagnosed.

CONCLUSIONS

The findings herein reported demonstrate that the FLOTAC technique can be successfully applied for recovering food-borne parasites of medical and veterinary concern in food matrices.

Seroprevalence of Neospora caninum and Toxoplasma gondii in dogs from an urban area of North-eastern Brazil: a spatial approach

INTRODUCTION

The present study aimed to assess the seroprevalence and spatial distribution of Neospora caninum and Toxoplasma gondii in dogs.

METHODS

Blood samples (n = 241) were collected and analyzed for the presence of anti-N. caninum and anti-T. gondii antibodies. The spatial distribution was evaluated using kernel density estimation (KDE).

RESULTS

Anti-N. caninum and anti-T. gondii antibodies were detected in 24.06% (58/241) and 9.54% (23/241) of samples, respectively. A heterogeneous spatial distribution of positive dogs was observed across the city.

CONCLUSIONS

These data are pivotal for better understanding the dynamics of infection caused by these protozoa in the canine population.

Evaluation of Serum Biochemical Parameters, Structural Changes, Immunohistochemistry and Parasite Load in the Urinary System of Dogs Infected Naturally by Leishmania infantum

The aim of this study was to evaluate the histopathological changes in the urinary system and their correlation with serum biochemical parameters, parasite load and immunodetection of amastigotes in 30 dogs infected naturally by Leishmania infantum. The major histological changes were glomerulonephritis and interstitial nephritis. Serum biochemistry demonstrated that the dogs had progressive loss of renal function. L. infantum amastigotes were detected immunohistochemically in all parts of the urinary system, except the ureters. There was a correlation between parasite load, severity of histopathological changes and immunodetection of the parasites, but parasite load was not correlated with the serum biochemical parameters evaluated.

Análise epistemológica dos conhecimentos científicos sobre Toxocara sp. com ênfase na infecção humana

Resumo Este artigo objetivou analisar a evolução do conhecimento sobre Toxocara sp. em seu aspecto zoonótico por meio de dados científicos entre os anos de 1996 a 2015 utilizando a epistemologia como ferramenta. A análise epistemológica da evolução do conhecimento sobre o aspecto zoonótico de Toxocara sp. no Brasil demonstrou que, de uma maneira geral, foram agregadas poucas novas informações as quais tiveram, ao longo do período estudado, absorção lenta, descontínua, e não foram inseridas na realidade social do ponto de vista de Saúde Pública.

Screening of Cercopithifilaria bainae and Hepatozoon canis in ticks collected from dogs of Northeastern Brazil

Rhipicephalus sanguineus sensu lato (s.l.) is one of the most widespread ixodid ticks and is a competent vector of several vector-borne pathogens of veterinary and medical concern. For instance, this tick species transmits nematodes of the genus Cercopithifilaria and protozoa of the genus Hepatozoon to carnivores, including dogs. Here we investigated the occurrence of Cercopithifilaria spp. and Hepatozoon spp. in a population of ticks collected from naturally infested dogs living in rural areas of Northeastern Brazil. From August 2016 to June 2017, 758 tick specimens (mean ticks per month = 68.9 ± 71.4) were sampled from 75 dogs (mean ticks per dog = 10.11 ± 5.2) and dissected under a stereomicroscope in order to visualize Cercopithifilaria spp. larvae and Hepatozoon spp. oocysts and sporocysts. R. sanguineus s.l. was the only species collected, peaking in September (n = 273) and decreasing in February 2017 (n = 39). Different larval stages of Cercopithifilaria bainae were identified in 7 out of 758 (0.93%) ticks. In addition, 4 specimens (0.53%) were positive for oocysts and free sporocysts of Hepatozoon canis. The identity of both species of parasites was molecularly confirmed. These results account for the predominance of R. sanguineus (s.l.) in domestic dogs from rural locations of the study area, as well as for the presence C. bainae and H. canis in these tick populations.

Survey on helminths and protozoa of free-living Neotropical bats from Northeastern Brazil

Bats are considered important reservoirs of pathogens of veterinary and medical relevance worldwide. However, despite the increasing attention paid towards the central role of bats in the spreading of some zoonotic infections, studies on their own parasites remain patchy especially in Neotropical regions. Understanding the relationships occurring between bats and their pathogens is a crucial step to determine the implications undermining the ecology and biology of these animals. The present study aims to assess the endoparasitic fauna of Neotropical bats from Northeastern Brazil, with a particular focus on helminths and protozoa. From October 2016 to March 2017, 54 fresh faecal samples were collected in stable shelters inhabited by three different bat species (i.e., Molossus molossus, Myotis lavali and Noctilio albiventris). Samples were analysed using four different techniques (i.e., Centrifugal Sedimentation, Flotation Technique, Spontaneous Sedimentation Technique and FLOTAC^®). A total of 96.29% (52/54) samples were positive for at least one gastrointestinal parasite and 11 different families were identified. In particular, 63.6% (7/11) of the families were of helminths and 36.4% (4/11) of protozoa. Helminths were classified into two different classes (Nematoda and Cestoda) and seven families, whereas the four protozoa classes detected (i.e., Coccidia, Gregarinomorphe, Lobosea and Zoomastigophora) into four families. Eggs of Ancylostomatidae and Hymenolepididae were the most abundan. The findings of this present study demonstrate that Neotropical bats from Northeastern Brazil are parasitized by a wide number of parasites, and some of them may have important implications for Public Health.

Rickettsia amblyommatis infecting Amblyomma pseudoconcolor in area of new focus of spotted fever in northeast Brazil

In Brazil, active infections of Rickettsia spp. is confirmed in all regions, involving various species of ticks. During investigation of a new focus of Spotted Fever (SF) incidence in the state of Pernambuco, northeastern Brazil, tick species Rhipicephalus sanguineus sensu lato (Latreille), and Amblyomma pseudoconcolor were collected from one Canis familiaris and four Euphractus sexcinctus, respectively, and analized for the presence of rickettsial genes. Ten A. pseudoconcolor ticks (90.9%) were found to be infected with Rickettsia, whereas no evidence of Rickettsia spp. was found in R. sanguineus s. l. Genetic analysis based of five rickettsial genes showed that the detected strain is most closely related to Rickettsia amblyommatis (formerly Candidatus Rickettsia amblyommii). R. amblyommatis was, for the first time, detected in Amblyomma pseudoconcolor and the results pointed to this tick like a potential vector in the enzootic cycle of R. amblyommatis in a typical semiarid Brazilian savannah region. In conclusion, despite the need for further studies to confirm if R. amblyommatis was responsible for the observed case in the state of Pernambuco, the presence of this bacterium during an SF focussed investigation should be a major concern in terms of public health due the capacity of SF for rapid and extensive dispersion within Brazilian territory.

Fatal case of spotted fever in a patient from Northeastern Brazil

Spotted fevers are diseases caused by bacterial agents belonging to the spotted-fever (SF) group of the genus Rickettsia. The first documented case of SF in Pernambuco State, Northeast Brazil, was reported here. Also, it is the first case described of fatal SF in Northeast region of Brazil. The patient was a resident of Arcoverde municipality and the probable site of infection lies in Sertania municipality, both in Pernambuco State, a semi-arid region of Brazil. The patient had not visited other areas where SF is endemic. The patient showed clinical manifestations and epidemiological exposure compatible with SF, and the infection was confirmed by molecular biology techniques.

Gastrointestinal parasites in feral cats and rodents from the Fernando de Noronha Archipelago, Brazil

Gastrointestinal parasites are important pathogens affecting animals, some of them are of medical and veterinary concern. Although the dynamic of parasitic infections is a complex phenomenon that has been studied under experimental conditions, it shows several gaps in knowledge, especially in insular regions where a confined population of animals and parasites co-exists. In this study was assessed the parasitism by endoparasite gastrointestinal in feral cats (n = 37) and rodents (n = 30) from the Fernando de Noronha Archipelago; in addition, the risk of human infection and ecological implications of these findings were discussed. Out of all samples analysed, 100% scored positive for the presence of gastrointestinal parasites in both feral cats and rodents. A total 17 genera and/or species of endoparasite gastrointestinal were identified, Ancylostoma sp., Strongyloides sp., Trichuris campanula and Toxocara cati were the parasites more frequently in feral cats. In rodents Eimeria sp., Strongyloides sp. and Trichuris muris were parasites more frequently herein detected. Human population living in this area are at risk of parasite infections due to the population of rodents and feral cats in the archipelago.

Detection and molecular characterization of Trypanosoma (Duttonella) vivax in dairy cattle in the state of Sergipe, northeastern Brazil

Abstract Trypanosoma (Duttonella) vivax is an important cause of economic losses among feedlot cattle. These losses are related to the morbidity, mortality, reproductive issues and decreased production. It is known that the clinical signs observed in infections by this protozoon are similar to other hemoparasitosis, which difficult the diagnosis. Therefore, the aim of this study was to detect and molecularly characterize an outbreak of trypanosomiasis caused by T. (D.) vivax in dairy cattle in the municipality of São Miguel Aleixo, state of Sergipe, Brazil. Blood samples from cattle (n = 15) presenting clinical signs compatible with trypanosomiasis were collected and parasitological and molecular evaluated. Among the samples analyzed, 34% (5/15) were positive from blood smears, 60% (9/15) from the buffy coat method and 80% (12/15) from the molecular method. The DNA sequence obtained (659 bp) showed 99% similarity to T. (D.) vivax sequences that are available in the GenBank database. The presence of this protozoon in cattle herds is a problem for producers. Diagnosing trypanosomiasis is problematic because its evolution is similar to that of other parasitic blood diseases. In addition, this is the first report of infection by T. (D.) vivax in cattle in the state of Sergipe, northeastern Brazil.

Cryptosporidium spp. and Giardia sp. in aquatic mammals in northern and northeastern Brazil

Cryptosporidium and Giardia are protozoans that can infect humans and wild and domestic animals. Due to the growing importance of diseases caused by protozoan parasites in aquatic species, we aimed to evaluate the frequency of infection by Cryptosporidium spp. and Giardia sp. in aquatic and marine mammals in the northern and northeastern regions of Brazil. We collected 553 fecal samples from 15 species of wild-ranging and captive aquatic mammals in northern and northeastern Brazil. All samples were analyzed by the Kinyoun technique for identification of Cryptosporidium spp. oocysts. Giardia sp. cysts were identified by means of the centrifugal-flotation technique in zinc sulfate solution. Subsequently, all samples were submitted for direct immunofluorescence testing. The overall frequency of infection was 15.55% (86/553) for Cryptosporidium spp. and 9.04% (50/553) for Giardia sp. The presence of Cryptosporidium spp. was detected in samples from 5 species: neotropical river otter Lontra longicaudis (15.28%), giant otter Pteronura brasiliensis (41.66%), Guiana dolphin Sotalia guianensis (9.67%), Amazonian manatee Trichechus inunguis (16.03%), and Antillean manatee T. manatus (13.79%). Giardia sp. was identified in L. longicaudis (9.23%), P. brasiliensis (29.16%), pygmy sperm whale Kogia breviceps (100%), dwarf sperm whale K. sima (25%), S. guianensis (9.67%), T. inunguis (3.81%), and T. manatus (10.34%). This is the first report of Cryptosporidium spp. in L. longicaudis, P. brasiliensis, and S. guianensis, while the occurrence of Giardia sp., in addition to the 2 otter species, was also identified in manatees, thus extending the number of hosts susceptible to these parasitic agents.

Phlebotomines in an area endemic for American cutaneous leishmaniasis in northeastern coast of Brazil

Abstract Phlebotomines have worldwide distribution with many species present in Brazil, including the northeastern region, where the fauna is very diverse. The aim of this study was to identify the sandfly fauna in an area endemic for American cutaneous leishmaniasis (ACL) in the state of Pernambuco. Sandflies were caught on three consecutive nights every month from October 2015 to September 2016, from 5 pm to 5 am, using seven light traps of Centers for Disease Control (CDC) type. Females were identified and used for molecular Leishmania detection. A total of 2,174 specimens belonging to ten species were collected: Lutzomyia choti (88.2%; 1,917/2,174) was the most abundant species, followed by Lutzomyia whitmani (8.1%; 176/2,174) and Lutzomyia sordellii (1.5%; 33/2,174). The majority of the specimens were collected in peridomestic areas (64.1%; 1,394/2,174) and during the rainy period. All the samples examined were negative for Leishmania spp. The presence of Lutzomyia whitmani indoors and in peridomestic areas indicates that the inhabitants of this area are exposed to the risk of infection by the parasites responsible for ACL.

Cat-rodent Toxoplasma gondii Type II-variant circulation and limited genetic diversity on the Island of Fernando de Noronha, Brazil

Background

In Brazil, studies on animals and humans in mainland areas have shown that most strains of Toxoplasma gondii are pathogenic to mice and exhibit great genetic variability.

Results

In this study, using a set of 11 PCR-RFLP and 15 microsatellite markers, we isolated and genetically characterised T. gondii strains from one cat and three rats on Fernando de Noronha Island. The cat had antibodies to T. gondii, which were revealed using a modified agglutination test (MAT, cut-off 1:25) and the seroprevalence among the 46 rodents was 15.2%. Viable T. gondii was isolated from one cat (TgCatBrFN1), two brown rats (TgRatnoBrFN1 and TgRatnoBrFN2) and one black rat (TgRatraBrFN1). Unlike the strains from mainland Brazil, these isolates were not pathogenic to outbred mice. The genotypes of these strains were compared with strains previously isolated on the island and in mainland Brazil. The analysis based on microsatellite data showed a limited genetic diversity of T. gondii on Fernando de Noronha Island with the majority of strains clustered into the following three groups: type II, III, and Caribbean 1.

Conclusions

There was little variation among strains within the same group, suggesting that the majority of strains circulating on Fernando de Noronha are derived from only a few strains that were recently introduced to the island, likely from imported cats. Except for the strain belonging to the Caribbean 1 group that originates from northeast Brazil, there was little evidence that strains from the other groups were introduced to Fernando de Noronha via mainland Brazil.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2150-4) contains supplementary material, which is available to authorized users.