Phlebotomine sandflies and the spreading of leishmaniases and other diseases of public health concern

Epidemiologic profile of oriental sore caused by Leishmania parasites in a new endemic focus of cutaneous leishmaniasis, southern Iran

Cutaneous leishmaniasis (CL) is the first and most important vector-borne zoonotic disease transmitted by sand flies in Iran. As a parasitic disease in the Old World, it is a complex zoonosis with multiple vertebrate hosts and arthropod vectors of pathogenic flagellate protozoan in the genus of Leishmania in different parts of its range. Phlebotomine sand flies are proven as vectors of this parasite which can be transmitted through the bite of an infected female sand fly distributed in almost all parts of Iran. This research performed on all CL patients as that were registered into special forms by physicians and experts during the study period 2006-2013 in the county town of Fasa, Iran. Data were analyzed by Chi square test using SPSS 17 statistics software. Overall, 1,908 patients (59.18 %) lived in rural and 1,316 (40.82 %) lived in urban areas. All ages were between 1 and ≥30 year. The most frequent age group was ≥20 years (54.6 %). Sex ratio of patients was almost 1:1 (1,561; 48.42 % male vs. 1,663; 51.58 % female). Most of them (66.84 %) had wet lesions and those with dry lesions were less frequent (33.16 %). There was a significant difference between the frequencies of these two groups (P < 0.05). Hand ulcers were the most prevalent part of body (43.24 %). The highest prevalence rate (35.14 %) of lesions occurred in autumn. The unstable trend of this disease in different years and its relatively high disease burden affecting all age groups in Fasa with respect to other counties in Iran showed that it was most likely an endemic disease in this region.

Leishmaniosis of companion animals in Europe: an update

Leishmaniosis caused by Leishmania infantum is a vector-borne zoonotic disease endemic in southern Europe, but which is spreading northwards. Millions of dogs, cats and other non-conventional companion animals susceptible to L. infantum, living in European households, may develop a severe disease and contribute to the spread of leishmaniosis because of travelling or re-homing. Dogs are the main reservoir but other new reservoirs have recently been incriminated. Sand flies remain the sole proven vector and non-vectorial transmission has been reported at individual level and in areas where the vector is absent. Clinical disease affects only a proportion of infected dogs and a complex genetic background of immune response is responsible for this susceptibility. There is a wide range of serological and parasitological diagnostic tools available whose cost-effective use depends on a reasoned approach. Clinical response to treatment of sick dogs is variable. Clinical cure is often obtained but clinical recurrence can occur and post-therapy follow up should be maintained life-long. In Europe, vaccination can be combined with individual protection with pyrethroids as part of an integrated approach to prevention. L. infantum is the only species isolated from cats in Europe and xenodiagnosis substantiated that infected cats are infectious for sand flies. Feline infection may be frequent in endemic areas, but prevalence is generally lower than in dogs. When cats are tested by both serological and molecular techniques discordant results are often observed. Feline cases have been reported from endemic areas in Italy, France, Spain and Portugal, but four cases were also diagnosed in Switzerland in cats that had travelled to or been imported from Spain. Half of the cases were diagnosed in cats with impaired immune responses. Clinical manifestations compatible with feline leishmaniosis include lymph node enlargement, skin and mucocutaneous lesions, ocular lesions, chronic gingivostomatitis, hypergammaglobulinemia, and normocytic normochromic anemia. Cats have been empirically treated with some drugs used in dogs. Due to polymorphic clinical picture and the insidious progressive course, leishmaniosis can persist for a long time before dogs or cats are brought to a veterinarian and so diagnosis can be delayed. Exotic or new Leishmania spp. have been reported in humans, animals and vectors in Europe. This changing situation requires attention in Europe for designing epidemiological studies and control measures.

Phlebovirus and Leishmania detection in sandflies from eastern Thrace and northern Cyprus

Background

Phlebotomine sandflies are vectors of several pathogens with significant impact for public health. This study was conducted to investigate and characterize phlebovirus and Leishmania infections in vector sandflies collected in the eastern Thrace region in Turkey and Northern Cyprus, where previous data indicate activity of these agents.

Methods

Field sampling of sandflies was performed at 4 locations in Edirne and Tekirdag provinces of eastern Thrace and at 17 locations in Lefkosa, Girne, Magosa and Guzelyurt provinces of northern Cyprus. In sandfly pools, phlebovirus RNA and Leishmania DNA were screened via a generic polymerase chain reaction (PCR) and kinetoplast minicircle PCR, respectively. Selected sandfly specimens unsuitable for pathogen detection were identified to species level. Cytochrome oxidase 1 gene region was used for DNA barcoding of selected specimens and pathogen positive pools. Positive amplicons were cloned and characterized by sequencing.

Results

A total of 2690 sandflies, collected from Eastern Thrace (15.4%) and Northern Cyprus (84.6%) were evaluated. Morphological examination of 780 specimens from Cyprus exhibited Phlebotomus perfiliewi sensu lato (72.6%), Phlebotomus tobbi (19.7%), Phlebotomus papatasi (2.8%), Laroussius sp. (1.6%) and Sergentomyia azizi (1.6%), Sergentomyia sp. (0.9%), Sergentomyia minuta (0.5%) and Phleobotomus jacusieli (0.1%) species. Pathogen screening was performed in 1910 specimens distributed in 195 pools. In eight pools of P.tobbi sandflies collected in Cyprus, Leishmania infantum DNA was demonstrated. Toscana virus (TOSV) genotype A sequences were identified in two pools of P. perfiliewi s.l. and one pool of P.tobbi sandflies from Cyprus. Co-infection of TOSV and Leishmania infantum was characterized in a P.tobbi pool. Sequences belonging to novel phleboviruses are revealed in three P. perfiliewi s.l. pools. One sequence, provisionally named Edirne virus, identified in Edirne province in eastern Thrace, demonstrated the highest rate of genomic similarity to Adria and Salehabad viruses. Furthermore, Girne 1 and Girne 2 viruses, identified in Girne province, revealed similarities to TOSV and Sandfly Fever Sicilian virus and related strains, respectively.

Conclusions

Activity of TOSV genotype A strains in Cyprus and co-infection of sandfly vectors with L. infantum was documented for the first time. Novel phlebovirus strains of unknown medical significance was identified in sampling regions.

The first report of autochthonous non-vector-borne transmission of canine leishmaniosis in the Nordic countries

Background

Leishmania spp. are zoonotic protozoans that infect humans and other mammals such as dogs. The most significant causative species in dogs is L. infantum. In dogs, leishmaniosis is a potentially progressive, chronic disease with varying clinical outcomes. Autochthonous cases of canine leishmaniosis have not previously been reported in the Nordic countries.

Results

In this report we describe the first diagnosed autochthonous cases of canine leishmaniosis in Finland, in which transmission via a suitable arthropod vector was absent. Two Finnish boxers that had never been in endemic areas of Leishmania spp., had never received blood transfusions, nor were infested by ectoparasites were diagnosed with leishmaniosis. Another dog was found with elevated Leishmania antibodies. A fourth boxer dog that had been in Spain was considered to be the source of these infections. Transmission occurred through biting wounds and semen, however, transplacental infection in one of the dogs could not be ruled out.

Two of the infected dogs developed a serious disease and were euthanized and sent for necropsy. The first one suffered from membranoproliferative glomerulonephritis and the second one had a chronic systemic disease. Leishmania sp. was detected from tissues by PCR and/or IHC in both dogs. The third infected dog was serologically positive for Leishmania sp. but remained free of clinical signs.

Conclusions

This case report shows that imported Leishmania-infected dogs may pose a risk for domestic dogs, even without suitable local arthropod vectors.

Persistence of phlebotomine Leishmania vectors in urban sites of Catania (Sicily, Italy)

Background

Pioneering research on “Mediterranean Kala-Azar” carried out by Adler and Theodor early in the past century (~1930s) had identified Catania city (Sicily) as a major focus of the disease nowadays known as zoonotic visceral leishmaniasis (VL). Despite the fact that disease in both humans and dogs has continued to be highly prevalent in the Catania province up to the present times, research on Leishmania vectors in this urban focus dates back to that distant period. This study aimed to evaluate the persistence and current composition of the sand fly fauna in urban environments of Catania in recent years, 2006 and 2013.

Methods

In 2006 fifty-one suitable collecting sites were identified within 44 sub-units of a grid drawn to include the urban Catania area. In 2013 the survey was restricted to four of the most productive and representative sites resulting from the 2006 survey. In both periods 3 collections per month were performed using standard sticky traps set for 3 days in wall holes/cavities along public roads, from the end of April through December.

Results

43/51 sites (84.3%) were found positive for sand flies. The 2006 collections accounted for a total of 4341 specimens including six species. Among competent Leishmania vector species, P. perniciosus was the most prevalent (36.5%) being identified in all sand fly-positive sites, with significant abundance in those of the old city centre. Other species of interest were P. sergenti (2.5%) and P. neglectus (1.5%). The 2013 survey produced 1130 sand flies, of which 39.5% were P. perniciosus, 1.6% P. sergenti and 0.7% P. neglectus. A search for Leishmania DNA in a small sample of 72 P. perniciosus females revealed 11% infection prevalence.

Conclusions

Our findings from an old urban focus of leishmaniasis demonstrate that phlebotomine sand flies have adapted fairly well to the drastic environmental changes that have occurred in cities of the Western world in the past century and still represent a potential risk for Leishmania transmission.

Human and entomological surveillance of Toscana virus in the Emilia-Romagna region, Italy, 2010 to 2012

Toscana virus (TOSV), transmitted by phlebotomine sandflies, is recognised as one of the most important causes of viral meningitis in summer in Mediterranean countries. A surveillance plan based on both human and entomological surveys was started in 2010 in the Emilia-Romagna region, Italy. Clinical samples from patients with neurological manifestations were collected during 2010 to 2012. The surveillance protocol was improved during these years, allowing the detection of 65 human infections. Most of these infections were recorded in hilly areas, where sandflies reach the highest density. Entomological sampling around the homes of the patients resulted in a low number of captured sandflies, while later sampling in a hilly area with high number of human cases (n=21) resulted in a larger number of captured sandflies. Using this approach, 25,653 sandflies were sampled, of which there were 21,157 females, which were sorted into 287 pools. TOSV RNA was detected by real-time PCR in 33 of the pools. The results highlighted the role of Phlebotomus perfiliewi as the main vector of TOSV and a potential link between vector density and virus circulation. This integrated system shows that an interdisciplinary approach improves the sensitiveness and effectiveness of health surveillance.

Multi-modal analysis of courtship behaviour in the old world leishmaniasis vector Phlebotomus argentipes

Background

The sand fly Phlebotomus argentipes is arguably the most important vector of leishmaniasis worldwide. As there is no vaccine against the parasites that cause leishmaniasis, disease prevention focuses on control of the insect vector. Understanding reproductive behaviour will be essential to controlling populations of P. argentipes, and developing new strategies for reducing leishmaniasis transmission. Through statistical analysis of male-female interactions, this study provides a detailed description of P. argentipes courtship, and behaviours critical to mating success are highlighted. The potential for a role of cuticular hydrocarbons in P. argentipes courtship is also investigated, by comparing chemicals extracted from the surface of male and female flies.

Principal Findings

P. argentipes courtship shared many similarities with that of both Phlebotomus papatasi and the New World leishmaniasis vector Lutzomyia longipalpis. Male wing-flapping while approaching the female during courtship predicted mating success, and touching between males and females was a common and frequent occurrence. Both sexes were able to reject a potential partner. Significant differences were found in the profile of chemicals extracted from the surface of males and females. Results of GC analysis indicate that female extracts contained a number of peaks with relatively short retention times not present in males. Extracts from males had higher peaks for chemicals with relatively long retention times.

Conclusions

The importance of male approach flapping suggests that production of audio signals through wing beating, or dispersal of sex pheromones, are important to mating in this species. Frequent touching as a means of communication, and the differences in the chemical profiles extracted from males and females, may also indicate a role for cuticular hydrocarbons in P. argentipes courtship. Comparing characteristics of successful and unsuccessful mates could aid in identifying the modality of signals involved in P. argentipes courtship, and their potential for use in developing new strategies for vector control.

The sand fly Phlebotomus argentipes transmits Leishmania parasites through female blood-feeding. These parasites cause leishmaniasis, a potentially fatal disease for which there is no vaccine. Understanding how insect vectors behave can aid in developing strategies to reduce disease transmission. Here, we investigate courtship behaviour in P. argentipes. Courtship is critical to an organism's life cycle, as it is essential for mating and reproduction. We show that courtship in this species begins with the male wing-flapping while approaching the female. This behaviour may suggest production of audio signals, or dispersal of chemicals from the male, which the female finds attractive. There then follows a period of touching between males and females prior to copulation. This behaviour may function in the transmission and reception of chemical signals, present on the insect surface. Many insects use these kinds of chemicals in courtship, and here we show differences in the chemicals extracted from the cuticle of male and female P. argentipes. Both males and females were found to be able to reject a potential mate. Understanding why some P. argentipes are more attractive than others could help identify the signals essential to reproduction, and their potential for use in vector control.

Characterization of breeding sites of Phlebotomus orientalis - the vector of visceral leishmaniasis in northwestern Ethiopia

We studied breeding sites of Phlebotomus orientalis (Diptera: Psychodidae) the vector of visceral leishmaniasis in northern Ethiopia. Although numbers were rather small, 165 sand flies were captured emerging from vertisol cracks. The most productive breeding sites were cracked vertisols, dry river banks and close to trees. No sand flies were caught emerging from sandy clay loam soils in peri-domestic habitats but a few were captured emerging from gaps in a stone wall. Abiotic parameters in vertisols close to trees and in open field from which P. orientalis had emerged, were compared. Soil pH was slightly alkaline and salinity was low. Organic matter contents were similar in both sites. Temperatures and RH remained relatively stable near trees from the end of the rainy season through mid dry season, yet fluctuated markedly at the shallower depth in the open field. During the rainy season, cracks in the soil were sealed resulting in significant lowering of the oxygen concentrations near the tree. Gravimetric water content of soil near trees was lower than open field at shallow depth but similar deeper down. We conclude that ambient conditions suitable for sand fly larvae at shallow depths (45cm) are restricted to areas close to trees. However, deeper in vertisols (90cm) suitable conditions are apparently maintained throughout the dry season even in open fallow fields.

Anthropic effects on sand fly (Diptera: Psychodidae) abundance and diversity in an Amazonian rural settlement, Brazil

Sand flies (Diptera: Psychodidae) are responsible for the transmission of protozoan parasites that cause leishmaniases. They are found predominantly in forests, but some species exploit environments that have been subject to deforestation and subsequent human colonization. Studies conducted in Brazil over the past 30 years show that some species are adapting to peri-urban and urban settings. We evaluated sand fly diversity and abundance in the rural settlement of Rio Pardo, Presidente Figueiredo Municipality, Amazonas State, Brazil. Settlement households were divided into four categories. These categories were determined by the human population density and the degree of deforestation in the immediate area. We used CDC light traps to sample the area surrounding 24 households (6 households in each category). Samples were taken on six occasions during September-November 2009 and June-August 2010. A total of 3074 sand fly specimens were collected, including 1163 females and 1911 males. These were classified into 13 genera and 52 species. The greatest abundance of sand flies and the greatest richness of species were observed in areas where human population density was highest. Our results show that changes in the human occupancy and vegetation management in rural settlements may affect the population dynamics and distribution of sand fly species, thereby affecting the local transmission of cutaneous leishmaniases.

Morphological keys for the identification of Italian phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae)

Background

Phlebotomine sand flies are small blood-feeding insects of great medical and veterinary significance. Their identification relies basically on the microscopic examination of key morphological characters. Therefore, identification keys are fundamental to any researcher dealing with these insects. The Italian fauna of phlebotomine sand flies consists of eight species (Phlebotomus perniciosus, Phlebotomus perfiliewi, Phlebotomus ariasi, Phlebotomus neglectus, Phlebotomus papatasi, Phlebotomus mascittii, Phlebotomus sergenti and Sergentomyia minuta), whose morphological delineation may be troublesome for non-taxonomists.

Methods

A total of 8,757 pictures were taken from the 419 selected phlebotomine sand fly specimens collected on different occasions. Twenty-eight characters for the males and 23 for the females were examined, resulting in a database containing over 10,000 entries. Representative phlebotomine sand fly specimens for each species available were selected and relevant characters were drawn with the aid of a camera lucida.

Results

After detailed morphological study of representative specimens, comprehensive identification keys based on key characters (e.g., pharynx and spermathecae of females and male terminalia) were elaborated.

Conclusions

The identification keys provided herein allow the identification of genera and species of phlebotomine sand flies of Italy and they will facilitate future studies on these medically important insects.

Leishmaniasis in the middle East: incidence and epidemiology

Leishmaniasis is a major health problem worldwide, with several countries reporting cases of leishmaniasis resulting in loss of human life or a lifelong stigma because of bodily scars. The Middle East is endemic for cutaneous leishmaniasis, with countries like Syria reporting very high incidence of the disease. Despite several countries establishing national control programs for containing the sandfly vector and treatment of infection, the disease continues to spread. In addition to the endemicity of the region for leishmaniasis, the Middle East has seen a great deal of human migration either for earning of livelihood or due to political upheaval in the region. These factors contribute to the spread and proliferation of the causative species Leishmania and its sandfly host. This review discusses the current epidemiological scenario in Iraq, Syria, Saudi Arabia, and Jordan, emphasizing the number of cases reported, vector species, Leishmania species, and treatment available. The data is primarily from WHO reports for each country and current and old literature.

Factors influencing the presence of sand flies in Majorca (Balearic Islands, Spain) with special reference to Phlebotomus pernicious, vector of Leishmania infantum

BACKGROUND

Although the Mediterranean island of Majorca is an endemic area of leishmaniosis, there is a lack of up-to-date data on its sand fly fauna, the last report dating from 1989. The aim of the present study was to provide information on the current sand fly distribution, the potential environmental factors favoring the presence of Phlebotomus perniciosus and which areas are at risk of leishmaniosis.

METHODS

In July 2008 sand fly captures were carried out in Majorca with sticky castor oil interception traps. The capture stations were distributed in 77 grids (5x5 km2) covering the entire island. A total of 1,882 sticky traps were set among 111 stations. The characteristics of the stations were recorded and maps were designed using ArcGIS 9.2 software. The statistical analysis was carried out using a bivariate and multivariate logistic regression model.

RESULTS

The sand fly fauna of Majorca is composed of 4 species: Phlebotomus perniciosus, P sergenti, P. papatasi and Sergentomyia minuta. P. perniciosus, responsible for Leishmania infantum transmission, was captured throughout the island (frequency 69.4 %), from 6 to 772 m above sea level. Through logistic regression we estimated the probability of P. perniciosus presence at each sampling site as a function of environmental and meteorological factors. Although in the initial univariate analyses the probability of P. perniciosus presence appeared to be associated with a wide variety of factors, in the multivariate logistic regression model only altitude, settlement, aspect, drainage hole construction, adjacent flora and the proximity of a sheep farm were retained as positive predictors of the distribution of this species.

CONCLUSIONS

P. perniciosus was present throughout the island, and thereby the risk of leishmaniosis transmission. The probability of finding P. perniciosus was higher at altitudes ranging from 51 to 150 m.a.s.l., with adjacent garrigue shrub vegetation, at the edge of or between settlements, and in proximity to a sheep farm.

Entomological study of sand flies (Diptera: Psychodidae: Phlebotominae) in Asalouyeh, the heartland of an Iranian petrochemical industry

OBJECTIVE

TO INVESTIGATE THE FAUNA AND SEASONAL ACTIVITY OF DIFFERENT SPECIES OF SAND FLIES (DIPTERA: Psychodidae: Phlebotominae) in Asalouyeh, the heartland of an Iranian petrochemical industry, Southern Iran, as a oil rich district. Sand flies are the vectors of at least three different kinds of disease, the most important of which is leishmaniasis, and it is a major public health problem in Iran with increased annual occurrence of clinical episodes.

METHODS

A total of 3 497 sand flies of rural regions were collected by sticky traps fixed, and cleared in puris medium and identified morphologically, twice a month from April to March 2008.

RESULTS

Predominant species included four of genus Phlebotomus (Phlebotomus alexandri Sinton, 1928, Phlebotomus papatasi Scopoli, 1910, Phlebotomus bergeroti Parrot and Phlebotomus sergenti Parrot) and one of genus Sergentomyia (Sergentomyia tiberiadis Alder, Theodor & Lourie, 1930). The most prevalent species was Phlebotomus papatasi, presented 56.4% of the identified flies. The others were Phlebotomus sergenti (22.5%), Phlebotomus alexandri (4.5%), Phlebotomus bergeroti (12%) and Sergentomyia tiberiadis (5%) as well. The percentage of females (68%) was more than that of males (32%). The abundance of sand flies represented two peaks of activity; one in early May and the other one in the first half of September in the region.

CONCLUSION

Phlebotomus papatasi is the probable vector of zoonotic cutaneous leishmaniasis in the region. Further molecular studies are needed to determine the definite vector of the region.

Ecology of phlebotomine sand flies and Leishmania infantum infection in a rural area of southern Italy

Phlebotomine sand flies are insects of major medico-veterinary significance in the Mediterranean region, as they may transmit pathogens to animals and humans, including viruses and protozoa. The present study was conducted in southern Italy, in an area where visceral leishmaniasis caused by Leishmania infantum is endemic. Insects were collected monthly during two consecutive years using light traps set in five different ecologic contexts (i.e., a stonewall near a woodhouse, a tree near volcanic rocks in a high-altitude area, a tree trunk in a meadow habitat, a sheep stable, and a chicken coop) and weekly in one site (the garage of a private house). A total of 13,087 specimens were collected and six species identified (i.e., Phlebotomus perfiliewi, Phlebotomus perniciosus, Phlebotomus neglectus, Phlebotomus papatasi, Phlebotomus mascittii, and Sergentomyia minuta), representing 75% of the total number of phlebotomine species found in Italy. P. perfiliewi was the most abundant species, comprising 88.14% of the specimens identified. The greatest species diversity and abundance was recorded in human dwellings and in animal sheds. Sand flies were active from June to October, peaking in July-August in 2010 and July-September in 2011. Part of the females (n=8865) was grouped into 617 pools (range, 1-10 insects each) according to species, feeding status, day and site of collection. A total of four pools (10 non-engorged specimens each) and one engorged female of P. perfiliewi were positive for L. infantum. This study confirms that phlebotomine vectors in southern Italy are highly adapted to human-modified environments (e.g., animal sheds) and that P. perfiliewi is a major vector of L. infantum in some regions of southern Italy.

Molecular detection of Leishmania in phlebotomine sand flies in a cutaneous and visceral leishmaniasis endemic area in northeastern Brazil

Several phlebotomine sand fly species have been regarded as putative or proven vectors of parasites of the genus Leishmania in Brazil, but data for the northeastern region remains incipient. In this study, a total of 600 phlebotomine sand flies were grouped in pools of 10 specimens each and tested by a Leishmania genus-specific PCR and by a PCR targeting Leishmania (Leishmania) infantum. Fourteen out of 60 pools were positive by the genus-specific PCR, being five pools of L. migonei, seven of L. complexa, one of L. sordellii and one of L. naftalekatzi, which correspond to a minimal infection rate of 2.3% (14/600). Our results, associated with their known anthropophily and their abundance, suggest the participation of L. migonei and L. complexa as vectors of Leishmania in northeastern Brazil. Remarkably, this is the first time in this country that the detection of Leishmania DNA in L. sordellii and L. naftalekatzi has been reported, but future studies are necessary to better understand the significance of these findings.

Transmission potential of antimony-resistant leishmania field isolates

We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of parasite transmission by sand flies. All three resistant strains produced fully mature late-stage infections in sand flies; moreover, the resistant phenotype was maintained after the passage through the vector. These results highlight the risk of circulation of resistant Leishmania strains and question the use of human drugs for treatment of dogs as Leishmania reservoirs.

American Cutaneous Leishmaniasis in Panama: a historical review of entomological studies on anthropophilic Lutzomyia sand fly species

We review existing information on the epidemiology of American Cutaneous Leishmaniasis (ACL) in Panama, with emphasis on the bionomics of anthropophilic Lutzomyia sand fly species. Evidence from Panamanian studies suggests that there are six anthropophilic species in the country: Lutzomyia trapidoi, Lu. panamensis, Lu. gomezi, Lu. ylephiletor, Lu. sanguinaria and Lu. pessoana (Henceforth Lu. carrerai thula). In general, these taxa are abundant, widespread and feed opportunistically on their hosts, which make them potential transmitters of pathogens to a broad range of wildlife, domesticated animals and humans. Furthermore, nearly all man-biting species in Panama (with the exception of Lu. gomezi) expand demographically during the rainy season when transmission is likely higher due to elevated Leishmania infection rates in vector populations. Despite this, data on the distribution and prevalence of ACL suggest little influence of vector density on transmission intensity. Apart from Lu. trapidoi, anthropophilic species seem to be most active in the understory, but vertical stratification, as well as their opportunistic feeding behavior, could vary geographically. This in turn seems related to variation in host species composition and relative abundance across sites that have experienced different degrees of human alteration (e.g., deforestation) in leishmaniasis endemic regions of Panama.

Effect of night time-intervals, height of traps and lunar phases on sand fly collection in a highly endemic area for canine leishmaniasis

The activity of phlebotomine sand flies was monitored in a sub-urban area of Sicily in order to acquire data on seasonality and to elucidate the effect of the night time-intervals, height of traps from ground and lunar phases on the abundance of the capture. The study was conducted in the farm of the University of Messina (Italy). Light traps were placed as in the following: biweekly, from dusk to dawn, and from May to November; for three consecutive nights from 18:00 to 6:00, with the net bag being changed every 2h; for 30 days, at different heights from 18:00 to 6:00. A total of five species (i.e., Phlebotomus perniciosus, Phlebotomus neglectus, Phlebotomus sergenti, Phlebotomus perfiliewi, and Sergentomyia minuta), three of which are proven vectors of Leishmania infantum, were captured. The most abundant species was P. perniciosus (73.3%) followed by S. minuta (23.3%). The highest number of phlebotomine sand flies was collected in August and September with a peak of collection recorded in the evening (i.e., from 20:01 to 22.00). The number of phlebotomine sand flies collected at 50cm above the ground was significantly higher (P=0.041) than that captured at 150cm. Results of this study shed light on the ecology of main phlebotomine species in the Mediterranean area, and on the influence of some factors, such as time and height of traps, on the light trap capture efficiency.

A single-centre, open-label, controlled, randomized clinical trial to assess the preventive efficacy of a domperidone-based treatment programme against clinical canine leishmaniasis in a high prevalence area

The innate immune response acting immediately after initial infection with Leishmania parasites is known to play a relevant role in prevention against clinical progression of the disease. Domperidone is a dopamine D2 receptor antagonist that has shown to enhance the innate cell-mediated immune response. The aim of this study was to assess the preventive efficacy of a domperidone-based treatment programme against clinical canine leishmaniasis (CanL) in a high prevalence area. The study was performed with 90 healthy, seronegative dogs of different sex, age, weight and breed from a single veterinary clinic located in Valencia (Spain). Dogs were randomly allocated into two groups. Dogs in one group (domperidone-treated group; n=44) were administered an oral suspension of domperidone at 0.5 mg/kg bw/day during 30 consecutive days, every 4 months. Dogs in the other group (negative control group; n=46) were left untreated. A 21-month follow-up period was implemented covering two seasonal phases of the sand fly vector. During this period all animals underwent periodic clinical examinations and blood samplings for anti-Leishmania serological testing. Dogs seropositive for Leishmania (IFAT antibody titre≥1:80) plus at least one clinical sign consistent with CanL (indicative of active infection and incipient disease progression) were categorized as a 'prevention failure'. These dogs were withdrawn from the study after confirming the infection by direct observation of the parasite in smears of lymph nodes and/or bone marrow aspirates. The cumulative percentage of 'prevention failure' after 12 months was significantly lower in the domperidone-treated group than in the negative control group (7% versus 35%, p=0.003). Differences between groups persisted after 21 months (11% versus 48%, p<0.001). The prevention rate provided by domperidone was 80% during the first 12 months and 77% throughout the complete 21-month follow-up period, with odds ratios of 7.3 (p=0.001) and 7.15 (p<0.001), respectively, this indicating that the risk for domperidone-treated dogs to develop the clinical disease is quite 7 times lower than for dogs left untreated. The results of this study demonstrate that the implementation of a strategic domperidone-based treatment programme consisting in quarterly repeated 30-day treatments with domperidone effectively reduces the risk to develop clinical CanL in areas with high prevalence of the disease.

Evidence of Leishmania infantum infection in rabbits (Oryctolagus cuniculus) in a natural area in Madrid, Spain

Leishmaniasis is one of the most important neglected zoonosis and remains endemic in at least 88 developing countries in the world. In addition, anthropogenic environmental changes in urban areas are leading to its emergency world wide. Zoonotic leishmaniasis control might only be achieved by an integrated approach targeting both the human host and the animal reservoirs, which in certain sylvatic cycles are yet to be identified. Recently, hares have been pointed out as competent reservoirs of Leishmania infantum in Spain, but the role of other lagomorphs has not been clarified. Here, 69 rabbits (Oryctolagus cuniculus) from a natural area in Madrid in which a high density was present were analyzed using indirect (immunofluorescence antibody test, IFAT) and direct (PCR, culture) techniques. Fifty-seven (82.6%) of the animals were positive to at least one technique, with IFAT yielding the highest proportion of positive samples. L. infantum was isolated in 13% animals demonstrating the occurrence of infection in this setting. Our results suggest that rabbits could play a role of competent reservoir of L. infantum and demonstrate that the prevalence of infection is high in the analyzed area.

Viral isolates of a novel putative phlebovirus in the Marche Region of Italy

Thirty pools from 900 (540 females and 360 males) Phlebotomus perfiliewi sandflies collected during the summer of 2012 in the Fermo area (Marche Region, central Italy) were tested for the presence of Phleboviruses. A nested polymerase chain reaction was performed using degenerated primers amplifying a fragment of the polymerase gene (large segment) and a fragment of the nucleoprotein gene (small segment) of the genus Phlebovirus. One pool was positive for Toscana virus, as expected from results of studies in the area, and six pools were positive for a putative novel Phlebovirus. Virus isolation in Vero cells was performed. Minimum field infection rates/1,000 insects processed for the novel and Toscana viruses were 6.7 and 1.0, respectively. Phylogenetic analysis of the novel Phlebovirus, tentatively named Fermo virus, placed it in the Sandfly Fever Naples virus serocomplex.

Identification of phlebotomine sand flies (Diptera: Psychodidae) by matrix-assisted laser desorption/ionization time of flight mass spectrometry

Background

Phlebotomine sand flies are incriminated in the transmission of several human and veterinary pathogens. To elucidate their role as vectors, proper species identification is crucial. Since traditional morphological determination is based on minute and often dubious characteristics on their head and genitalia, which require certain expertise and may be damaged in the field-collected material, there is a demand for rapid, simple and cost-effective molecular approaches.

Methods

Six laboratory-reared colonies of phlebotomine sand flies belonging to five species and four subgenera (Phlebotomus, Paraphlebotomus, Larroussius, Adlerius) were used to evaluate the discriminatory power of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Various storage conditions and treatments, including the homogenization in either distilled water or given concentrations of formic acid, were tested on samples of both sexes.

Results

Specimens of all five analysed sand fly species produced informative, reproducible and species-specific protein spectra that enabled their conclusive species identification. The method also distinguished between two P. sergenti colonies originating from different geographical localities. Protein profiles within a species were similar for specimens of both sexes. Tested conditions of specimen storage and sample preparation give ground to a standard protocol that is generally applicable on analyzed sand fly specimens.

Conclusions

Species identification of sand flies by MALDI-TOF MS is feasible and represents a novel promising tool to improve biological and epidemiological studies on these medically important insects.

Comparative field study to evaluate the performance of three different traps for collecting sand flies in northeastern Italy

Three standard methods for collecting sand flies (sticky trap, CDC light trap, and CO2 trap) were compared in a field study conducted from June to October, 2012, at a site located in the center of a newly established autochthonous focus of canine leishmaniasis in northeastern Italy. Six traps (two sticky traps, two CDC light traps, and two CO2 traps) were activated at the same time for a single night every two weeks during the season of sand fly activity. A total of 5,667 sand flies were collected and 2,213 identified, of which 82.1% were Phlebotomus perniciosus, 17.4% P. neglectus, 0.3% Sergentomya minuta, and 0.2% P. mascitti. The performances of all traps were influenced by their position inside the site, increasing with proximity to the animal shelters. CO2 traps were more attractive for females of P. perniciosus and P. neglectus. CDC light traps showed an intermediate efficiency and were more attractive for P. neglectus, compared to other two traps. Results suggest that in northern Italy the CO2 trap is a suitable sampling method for sand fly monitoring programs that include transmitted pathogen surveillance.

Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems

The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

Presence of sandflies infected with Leishmania infantum and Massilia virus in the Marseille urban area

Leishmaniasis is considered a rural disease in Europe. However, circumstantial evidence has indicated urban transmission of leishmaniasis and phleboviruses in the urban area of Marseille, France. To investigate this urban transmission, sandflies were trapped in 33 locations in the urban area (horse farms, public gardens and a residential area). Sandflies were always captured: 87.8% were Phlebotomus perniciosus, a vector of Leishmania infantum and Toscana and Massilia viruses. RT-PCR and cell culture inoculation identified the Massilia virus in 2/99 pools of sandflies, and PCR identified Leishmania in 5/99. No dual infection was observed, but both pathogens were detected in samples from the same trapping site.

Studies on the sand fly fauna (Diptera: Psychodidae) in high-transmission areas of cutaneous leishmaniasis in the Republic of Suriname

BACKGROUND

Sand flies (Diptera: Psychodidae) are the vectors of Leishmania parasites, the causative agents of leishmaniasis. Cutaneous leishmaniasis is an increasing public health problem in the Republic of Suriname and is mainly caused by Leishmania (Vianna) guyanensis, but L. (V.) braziliensis, L. (L.) amazonensis, and L. (V.) naiffi also infect humans. Transmission occurs predominantly in the forested hinterland of the country. Information regarding the potential vectors of leishmaniasis in Suriname is limited. This study aims to broaden the knowledge about vectors involved in the transmission of cutaneous leishmaniasis in Suriname. For this purpose, sand flies were characterized in various foci of cutaneous leishmaniasis in the country, the districts of Para, Brokopondo, and Sipaliwini.

METHODS

Sand flies were collected in areas around mining plots and villages using CDC light traps in the period between February 2011 and March 2013. They were categorized by examination of the spermathecea (females) and the external genitalia (males).

RESULTS

A total of 2,743 sand fly specimens belonging to 34 different species were captured, including four species (Lutzomyia aragaoi, Lu. ayrozai, Lu. damascenoi, and Lu. sordellii) that had never before been described for Suriname. Five percent of the catch comprised Lu. squamiventris sensu lato, one female of which was positive with L. (V.) braziliensis and was captured in a gold mining area in Brokopondo. Other sand fly species found positive for Leishmania parasites were Lu. trichopyga, Lu. ininii, and Lu. umbratilis, comprising 32, 8, and 4%, respectively, of the catch. These were captured at gold mining areas in Brokopondo and Sipaliwini, but the Leishmania parasites they had ingested could not be identified due to insufficient amounts of DNA.

CONCLUSIONS

The sand fly fauna in Suriname is highly diverse and comprises Lutzomyia species capable of transmitting Leishmania parasites. Four new Lutzomyia species have been found, and four species - Lu. squamiventris (s.l.), Lu. trichopyga, Lu. ininii, and Lu. umbratilis - have been found to harbor Leishmania parasites. The latter were among the most abundant species captured. These observations may contribute to the understanding of leishmaniasis transmission and the development of control programs in Suriname.

Co-circulation of Toscana virus and Punique virus in northern Tunisia: a microneutralisation-based seroprevalence study

Background

In northern Tunisia, the co-circulation of two related sand fly-borne phleboviruses, Toscana virus (TOSV) and Punique virus (PUNV) was previously demonstrated. In contrast to TOSV, a prominent human pathogen, there is no data supporting that PUNV is capable to infect and cause disease to humans. We studied the respective involvement of TOSV and PUNV in human infections in northern Tunisia through a seroprevalence study.

Methods

The presence of TOSV and PUNV neutralising antibodies (NT-Ab) was tested in human sera collected from 5 districts of the governorate of Bizerte, and the titres of NT-Ab were estimated by microneutralisation (MN) assay.

Principal Findings

A total of 1,273 sera were processed. TOSV and PUNV NT-Ab were detected in 522 (41%) and 111 sera (8.72%) respectively. TOSV seroprevalence varied from 17.2% to 59.4% depending on the district. Analysis of TOSV geometric mean titre values demonstrated a constant increase according to the age. The vast majority of sera containing NT-Ab were found to be more reactive toward TOSV than PUNV. Indeed, past infections with PUNV and TOSV were undisputable for 5 and 414 sera, respectively.

Conclusions

PUNV may be capable to infect humans but at a low rate. TOSV is responsible for the vast majority of human infections by sand fly-borne phleboviruses in northern Tunisia. TOSV must be considered by physician and tested in diagnostic laboratories for patients with meningitis and unexplained fever in northern Tunisia.

In northern Tunisia, two different pheboviruses are known to circulate in sand fly population, Toscana virus (TOSV) and Punique virus (PUNV). In contrast to TOSV, a prominent human pathogen, there is no data supporting that PUNV is capable to infect humans and to cause a disease. We studied the respective involvement of TOSV and PUNV in human infections in northern Tunisia through a seroprevalence study. Because TOSV and PUNV are antigenically and genetically closely related, it is difficult to distinguish between them by using broadly reactive serological tests, such as enzyme-linked immunosorbent assay (ELISA). Thus, we developed a method of microneutralisation assay using the two viruses in a comparative manner. A total of 1,273 sera were processed. We provide first evidence to support (i) that Punique virus may be capable to infect humans but at a low rate, (ii) that TOSV, the most prevalent arbovirus in Southern Europe, is responsible for the vast majority of human infections by sand fly-borne phleboviruses in northern Tunisia. Therefore, it is important to consider TOSV as an important pathogen that needs to be included in all virological diagnostic concerning patients with meningitis and unexplained febrile illness originated from Northern Tunisia.

Leishmaniasis sand fly vector density reduction is less marked in destitute housing after insecticide thermal fogging

BACKGROUND

Insecticide thermal fogging (ITF) is a tool to control vector borne diseases. Insecticide application success for vector control has been associated with housing materials and architecture. Vector abundance is correlated with weather changes. Nevertheless, housing quality and weather impacts on vector abundance have been unaccounted for in most New World insecticide control trials for leishmaniasis vectors.

METHODS

We conducted a 15 month insecticide control trial that included two deltamethrin [6 mg a.i.m-2] based ITF interventions in 12 of 24 monitored houses at Trinidad de Las Minas, a hyperendemic cutaneous leishmaniasis transmission village in western Panamá. During the study we followed sand fly (SF) abundance, keeping track of rainfall and quantified housing quality using an index based on architecture and construction materials.

RESULTS

We found a 50 to 80% reduction in SF density in the fogged houses when compared with control houses, while controlling for seasonal changes in SF abundance associated with rainfall. We found heterogeneities in the reductions, as abundance changed according to SF species: Lutzomyia gomezi, Lu. panamensis, Lu. dysponeta and Lu. triramula reduced in density between 40% and 90% after ITF. In contrast, Lu. trapidoi density increased 5% after ITF. Differences in the impact of ITF were associated with housing quality, the most destitute houses, i.e., those with features that ease insect entrance, had a disproportionally larger SF abundance, in some cases with increased domiciliary SF density following the ITF.

CONCLUSION

Our results suggest the potential of insecticide application to control SF density and leishmaniasis transmission could depend on housing quality beyond insecticide efficiency.

The prevention of canine leishmaniasis and its impact on public health

Canine leishmaniasis (CanL) caused by Leishmania infantum is a vector-borne disease of great veterinary and medical significance. Prevention of CanL requires a combined approach including measures focused on dogs and the environment where the vectors perpetuate. Over past decades, considerable effort has been put towards developing novel and cost-effective strategies against CanL. Vaccination is considered among the most promising tools for controlling CanL, and synthetic pyrethroids are useful and cost-effective in reducing risk of L. infantum infection in dogs. The effectiveness of the use of vaccines plus repellents in preventing L. infantum infection and subsequent disease development should be assessed by means of large-scale, randomized controlled field trials because this combined strategy may become the next frontier in the control of CanL.

Paediatric visceral leishmaniasis in Italy: a 'One Health' approach is needed

Here we describe a case of paediatric visceral leishmaniasis recorded in an infant initially suspected for acute lymphoblastic leukaemia due to the clinical and haematological presentation. Eventually the patient was found positive for Leishmania infantum infection and successfully treated. This case emphasises how pivotal a ‘One Health’ approach is for diagnosing this zoonotic disease; highlighting the importance of including Visceral Leishmaniasis in the differential diagnosis of leukaemia-like syndromes in infants travelling to, and living in, the Mediterranean region.

Prevention of canine leishmaniosis in a hyper-endemic area using a combination of 10% imidacloprid/4.5% flumethrin

Background

Dogs are the main reservoir hosts of Leishmania infantum, the agent of human zoonotic visceral leishmaniosis. This study investigated the efficacy of a polymer matrix collar containing a combination of 10% imidacloprid and 4.5% flumethrin as a novel prophylactic measure to prevent L. infantum infections in young dogs from a hyper-endemic area of southern Italy, with a view towards enhancing current control strategies against both human and canine leishmaniosis.

Methodology/Principal Findings

The study was carried out on 124 young dogs, of which 63 were collared (Group A) while 61 were left untreated (Group B), from March-April 2011 until March 2012. Blood and skin samples were collected at baseline (April 2011) and at the first, second, third and fourth follow-up time points (July, September 2011 and November 2011, and March 2012, respectively). Bone marrow and conjunctiva were sampled at baseline and at the fourth follow-up. Serological, cytological and molecular tests were performed to detect the presence of L. infantum in the different tissues collected. At the end of the trial, no dog from Group A proved positive for L. infantum at any follow-up, whereas 22 dogs from Group B were infected (incidence density rate = 45.1%); therefore, the combination of 10% imidacloprid and 4.5% flumethrin was 100% efficacious for the prevention of L. infantum infection in young dogs prior to their first exposure to the parasite in a hyper-endemic area for CanL.

Conclusions

The use of collars containing 10% imidacloprid and 4.5% flumethrin conferred long-term protection against infection by L. infantum to dogs located in a hyper-endemic area, thus representing a reliable and sustainable strategy to decrease the frequency and spread of this disease among the canine population which will ultimately result in the reduction of associated risks to human health.

Canine leishmaniosis in the Old and New Worlds: unveiled similarities and differences

Canine leishmaniosis is a potentially life-threatening disease which is spreading geographically in the Old and New Worlds, where different diagnostic procedures, treatments, and control strategies are currently in place. This Opinion article outlines the similarities and differences between canine leishmaniosis in the Old and New Worlds, with emphasis on South America and Europe. Finally, it calls the attention of veterinary and public health authorities to standardize and improve practices for diagnosing, treating, and preventing the disease.