Field Evaluation of Two Different Treatment Approaches and Their Ability to Control Fleas and Prevent Canine Leishmaniosis in a Highly Endemic Area

On-host flea phenology and flea-borne pathogen surveillance among mammalian wildlife of the pineywoods of East Texas

Flea-borne diseases are endemic in Texas, U.S.A., with an increasing incidence of flea-borne typhus and cat scratch disease. Knowledge of flea natural history could provide information to protect public health, yet many knowledge gaps remain outside of plague-endemic regions. Our objective was to characterize seasonal activity patterns of fleas on common mammalian wildlife species and test fleas and wildlife for Rickettsia and Bartonella pathogens. We performed one year of monthly trapping for rodents and medium-sized mammals in a national forest with high recreational use and urban encroachment in East Texas. From 90 mammal captures representing seven species, 101 fleas were collected representing Polygenis spp., Ctenocephalides felis, and Orchopeas species. Virginia opossums (Didelphis virginianus) hosted 99% of the collected fleas (100 fleas) and a single flea was on an eastern woodrat (Neotoma floridana). Flea infestation prevalence of opossums was 79% (23/29). Mean flea abundance was 4.39 fleas, with intensity peaking in spring. One cat flea removed from an opossum was positive for Bartonella henselae. Furthermore, we identified tissue or blood of four raccoons (Procyon lotor) and one golden mouse (Ochrotomys nuttalli) positive for Rickettsia amblyommatis. These findings provide an ecological basis for the maintenance of vectors and pathogens from sylvatic settings.

Strategic use of 4 % deltamethrin impregnated-collar in seropositive dogs reduces the incidence of seroreactivity to visceral leishmaniasis in dogs from endemic areas

The effectiveness of a visceral leishmaniasis (VL) control strategy based on the application of 4 % deltamethrin impregnated collars (DIC) exclusively in seropositive dogs was assessed between 2018 and 2019, through a prospective study. The effectiveness of DIC-collaring was evaluated by comparing the incidence rate of anti-leishmanial antibodies among dogs from two endemic districts in Brazil. In one of the areas, the conventional control measure which is based on the non-compulsory euthanasia of LV seropositive dogs, was practiced by the official healthy service as a regular procedure, whereas strategic collaring, conceived in this study, was carried out in the other. Results of serological tests applied to serum samples collected from all domiciled dogs were evaluated in three consecutive times, spaced by around 200 days. Incidence rates of VL seroreactivity were compared between districts in the same period of time as well as within the same district, in consecutive periods. Based on the results, the risk of infection in the population under conventional control measure was up to four times higher than the risk of infection where DIC-collaring was used. The strategic use of collar proposed here emerged as a promising measure for VL control in dogs from endemic areas. Strategic collaring does not rely on the euthanasia of infected animals, an extremely controversial procedure, and instead of being used in all dogs, as collaring is normally recommended; only seropositive dogs are intervened. Strategic use of DIC has the potential to drastically reduce costs, if compared to mass collaring canine population.

Canine leishmaniasis caused by Leishmania Tropica in southeastern Iran: a case series study

Dogs are the primary reservoirs of Leishmania infantum (L. infantum), but Leishmania tropica (L. tropica) infection is also possible in dogs and can transmitted to humans. The southeast of Iran experiences a high prevalence of canine leishmaniasis (CanL), and veterinarians frequently encounter symptomatic cases. Therefore, from December 2017 to November 2022, the present case series was designed to assess the prevalence of CanL in owned dogs with cutaneous manifestations resembling CanL. A total of 500 owned dogs with dermal lesions from two endemic cities, Zabol and Kerman, were enrolled. Impression smears from skin lesions and popliteal lymph nodes were prepared from all cases, whereas blood samples were gathered from amastigote-positive dogs for serological and molecular surveys. Commercial ELISA was done on sera samples, and two-step nested PCR was used on extracted DNA to amplify variable fragments of the Leishmania species' kinetoplast DNA (kDNA). Leishman bodies were microscopically detected in 7.2% (36/500) of dermal smears. Of the 360 owned dogs from Zabol, 2 have been diagnosed with L. tropica, and 10 have been diagnosed with L. infantum. Out of 140 owned dogs from Kerman, 8 were identified with L. tropica infection, and 16 were infected with L. infantum. Molecular results revealed the presence of 750 full dual-band bases related to the L. tropica species in 10/36 (27.7%) cases, which showed a considerable increase in canine cutaneous leishmaniosis compared with previous studies in southeastern Iran. The noticeable prevalence of L. tropica in owned dogs indicated that the dog's role in cutaneous leishmaniosis should be re-evaluated as a possible animal reservoir in endemic areas.

New paradigms in the prevention of canine vector-borne diseases

The prevention of canine vector-borne diseases (CVBDs) is pivotal for the health and welfare of dogs as well as for reducing their zoonotic risk to humans. Scientific knowledge gained in recent years contributed to the development of new strategies for the control of these diseases in different social and cultural contexts. Here, we discuss recent advances in the prevention of vector-borne pathogens (VBPs) affecting dogs with a focus on those of zoonotic relevance.

New distribution patterns of Dirofilaria immitis in Italy

In recent decades, the number of autochthonous cases and foci of Dirofilaria immitis in dogs from southern regions has increased considerably, suggesting that the distribution of the species is not limited to northern Italian regions. This epidemiological picture emerges from case reports or studies in specific locations where outbreaks of heartworm disease have occasionally been reported together with the presence of mosquito vectors. To obtain a more comprehensive picture of the current distribution of D. immitis in southern Italy, a multicenter cross-sectional survey of canine filariasis was conducted. Owned and sheltered dogs (n = 1,987) were included in the survey regardless their breed, attitude and/or sex. All included dogs were older than 1 year and had no history of chemoprophylactic treatment against filarioses. A blood sample was collected from enrolled dogs and screened by modified Knott's test and, when positive, tested using D. immitis specific ELISA rapid test (SNAP 4DX, IDEXX). The overall microfilaremia prevalence was 17% (n = 338) being single-species infection (92.6%) more common that mixed (7.4%). Remarkably, D. immitis was the most frequent species detected with an overall prevalence of 11.4% (n = 227), followed by Dirofilaria repens (n = 74; 3.7%), and Acanthocheilonema reconditum (n = 12; 0.6%). Sheltered dogs were significantly more infected by D. immitis, as well as mongrel dogs and animals housed in rural areas. Data here reported indicate that D. immitis is largely present in southern Italy, raising awareness about the necessity of proper screening and chemoprophylactic treatments in exposed animals.

Determination of the effect of collars containing 10% w/w imidacloprid and 4.5% w/w flumethrin (Seresto®) on the incidence of Leishmania and other canine vector-borne pathogen infections in Greece

BACKGROUND

The objective of this field study was to assess the effect of treating a considerable portion of a dog population naturally exposed to canine vector-borne pathogens (CVBPs) in endemic areas with a 10% w/w imidacloprid/4.5% w/w flumethrin collar (Seresto®) on the transmission of CVBPs and the resulting incidence of infection.

METHODS

A total of 479 dogs from two sites were enrolled in the study. Collars were placed on all dogs continuously for 21 months, with replacement of the collar every 7 months. All dogs were examined, including body weight and blood/conjunctival swab collections, every 7 months. Serum samples were analysed for the presence of antibodies against Leishmania infantum, Ehrlichia canis and Anaplasma phagocytophilum. PCR assays were also performed on blood samples and conjunctival swab collected from the dogs for the presence of L. infantum, and on blood samples only for the presence of Ehrlichia spp. and Anaplasma spp. Sand flies were collected, identified to species level and molecularly tested for L. infantum throughout two vector activity seasons.

RESULTS

The results showed that the Seresto collar was safe with continuous use. At study inclusion, 419, 370 and 453 dogs tested negative for L. infantum, Ehrlichia spp. and Anaplasma spp., respectively (353 dogs tested negative for any pathogen). Overall, 90.2% of the dogs were protected from L. infantum infection on both sites combined. The entomological survey confirmed the presence of competent vectors of L. infantum at all monitored locations, namely the sand flies Phlebotomus neglectus and Phlebotomus tobbi, both of which are regarded as the most important competent vectors in the Mediterranean basin. All captured sand flies tested negative for L. infantum. Protection against ticks and fleas was high, with only two dogs showing a low number of ticks and seven dogs having low numbers of fleas at single evaluation time points. Across the entire study population, a number of dogs became infected with tick-transmitted pathogens, but prevention of transmission was 93% for E. canis and 87.2% for Anaplasma spp. when all cases from both sites were combined.

CONCLUSIONS

The Seresto® (10% w/w imidacloprid/4.5% w/w flumethrin) collar significantly reduced the risk of CVBP transmission when compared to previously observed incidences of CVBP infections in two highly endemic areas under field conditions.

Clinical Case of Feline Leishmaniosis: Therapeutic Approach and Long-Term Follow-Up

The response to allopurinol treatment and survival time of a case of feline leishmaniosis in a FIV co-infected cat is herein reported. In May 2019, a 13-year-old neutered European Shorthair male was referred due to weight loss and exfoliative dermatitis. Lymphadenomegaly and splenomegaly were detected upon clinical inspection, while the presence of several Leishmania infantum amastigotes were detected on splenic and lymphonodal fine needle aspiration (FNA). Allopurinol (10 mg/kg PO q 12 h) was administered. After two months, the cat's clinical symptoms disappeared, and the owners decided to interrupt the therapy. In February, two reddish nodular fleshy neoformations appeared in both eyes, and amastigotes of Leishmania were detected by cytology on conjunctival swabs. Allopurinol treatment was re-started at the same rate; the ocular lesions regressed in two weeks, and the owner again decided to interrupt the therapy. In July, the patient had a new relapse, but the owner, tired of continuous relapses, refused further treatment of the disease. The cat's health condition continued to worsen: in October 2021, the ocular lesions appeared again, and in November the patient died. This case underlines the effectiveness of allopurinol and highlights how interruption of treatment frequently leads to relapse, impairing the animal's health condition and prognosis.

Molecular and serological evaluation of visceral leishmaniasis in domestic dogs and cats in Maragheh County, north-west of Iran, 2018-2021

Objective

Zoonotic visceral leishmaniasis (VL) is caused by Leishmania infantum, of which dogs are the main reservoir. VL is endemic in the Middle East, also in some parts of Iran. Following reports of new cases of VL in children in Maragheh County, the non‐endemic area of the disease, we encouraged to conduct a preliminary study on domestic dogs and cats to identify their potential role as reservoirs for the disease.

Materials and Methods

This study was conducted during a period of 3 years from 2018 to 2021. Two hundred ownership dogs and 25 cats from Maragheh County, north‐west of Iran, were randomly screened. Blood samples were collected. A direct agglutination test (DAT) was used for the detection of anti‐L. infantum antibodies. Furthermore, buffy coat samples from the L. infantum seropositive animals were examined to detect parasite presence using polymerase chain reaction.

Results

Out of the total of 200 ownership dogs evaluated, 170 (85%) were male and 30 (15%) were female with a mean age of 4.3 years. Anti‐L. infantum antibodies (IgG cut‐off ≥ 1:320) were observed in 3.5% of dogs (7/200) by the DAT test. All seropositive dogs were identified in the first year of examination. Regarding molecular approaches in seropositive dogs, two samples were positive for a 565 bp kDNA minicircle gene specific for L. infantum. During the study period, no seropositive case was detected in the cats examined.

Conclusions

This study shows that the domestic cycle of L. infantum has been established in the studied region. It is necessary to increase the awareness and monitoring of the disease with the study of wild reservoirs periodically.

Efficacy of imidacloprid/flumethrin collar in preventing canine leishmaniosis in Brazil

The Leishmania infantum (synonym, Leishmania chagasi) causes life-threatening infection, namely canine leishmaniosis (CanL), which is a chronic zoonosis prevalent in various countries and spread by the bite of the infected Lutzomyia female sandfly in South America. The objective of the study was to assess the effectiveness of a polymer matrix collar containing made up of 10% imidacloprid and 4.5% flumetrin for the prevention of canine leishmaniosis from the hyperendemic region falling under Araçatuba municipality (Brazil). The research included a total of 146 dogs chosen from 75 households. Test were initiaded via physical examination, weighing, and biological sample collection (blood, popliteal lymph node, and conjunctival swab) of these dogs was done in March 2018 (Day 0; GA, control = 69, GB, treated = 77) to initiate lab tests. Post-inclusion, the animals were monitored on the 120th, 240th, 360th, and 480th days, respectively. The usage of collars continued between 0 to 480 days before being substituted in second (D240) and fourth (D480) follow-up visits. On the whole, 25 dogs in GA (36.2 percent) and 3 in GB (3.9 percent) were found positive for L. infantum infection in a minimum of one diagnostic test used in the research. Therefore, the average collar effectiveness for protection from L. infantum infection was 89.2% (p < 0.01). In the last follow-up, the average incidence density rate for GA was 30.7%, whereas, for GB, it was 2.9%. The imidacloprid/flumethrin collars evaluated in the research were found to be safe and extremely efficient for the prevention of L. infantum infection through Lutzomyia species among the large population of dogs in highly prone endemic regions. This is a dependable and efficient technique aimed at reducing the occurrence and propagation of this illness among the population of canines, which would eventually reduce the human-health-related hazards. In Brazil, Lutzomyia spp. is a leading vector of the infection; thus, the collar can be used to limit infection in dogs and humans. The first trial was conducted in Brazil, including a 10% imidacloprid/4.5% flumethrin collar. In the initial assessment, the efficiency of the collar was 91.0% (D0 to D240). The effectiveness was 90.0% in the second assessment (D240 to D480). The mean effectiveness of the collar was 89.2% during the protection of dogs against L. infantum. The collar used for this evaluation was extremely useful and safe. This article is protected by copyright. All rights reserved.

Elevated and sustained anti-feeding effect of Scalibor® deltamethrin collar against the sand fly Phlebotomus perniciosus in dogs confirmed for 1 year following treatment

Dogs are reservoir hosts for Leishmania infantum, a protozoan parasite transmitted by phlebotomine sand flies. The anti-feeding and fast-killing efficacy of Scalibor® deltamethrin collars against experimental Phlebotomus perniciosus challenges on dogs was determined over 1 year. Two groups of 8 dogs each were fitted with placebo (control) or deltamethrin collars (treated) on Day 0 and exposed to sand flies approximately every 28 days up to Day 364. After each exposure, anti-feeding and fast-killing efficacy rates were determined by comparing blood-fed or live insects, respectively, in the treated vs. the control group. Blood-fed and live sand flies were significantly less in treated dogs as compared to control dogs at each assessment. The anti-feeding efficacy rate exceeded 90% except on Day 337 (89%) but increased again (96%) on Day 364. Fast killing efficacy was <74% over the study when considering all flies. However, this value increased cumulatively to 98% when only blood-fed flies were compared between groups. Scalibor® collars are highly effective at preventing P. perniciosus blood-feeding and in fast-killing flies taking a blood meal for up to 1 year after application. These strong and long-lasting effects are an important strategic component for L. infantum transmission control.

Detection of Leishmania tarentolae in lizards, sand flies and dogs in southern Italy, where Leishmania infantum is endemic: hindrances and opportunities

Background

Leishmania tarentolae is a protozoan isolated from geckoes (Tarentola annularis, Tarentola mauritanica), which is considered non-pathogenic and is transmitted by herpetophilic Sergentomyia spp. sand flies. This species occurs in sympatry with Leishmania infantum in areas where canine leishmaniasis is endemic. In the present study, we investigated the circulation of L. tarentolae and L. infantum in sand flies, dogs and lizards in a dog shelter in southern Italy, where canine leishmaniasis by L. infantum is endemic.

Methods

Sheltered dogs (n = 100) negative for Leishmania spp. (March 2020) were screened by immunofluorescence antibody test (IFAT) using promastigotes of both species at two time points (June 2020 and March 2021). Whole blood from dogs, tissues of Podarcis siculus lizards (n = 28) and sand flies (n = 2306) were also sampled and tested by a duplex real-time PCR (dqPCR). Host blood meal was assessed in sand flies by PCR.

Results

Overall, 16 dogs became positive for L. infantum and/or L. tarentolae by IFAT at one or both sampling periods. One canine blood sample was positive for L. infantum, whilst two for L. tarentolae by dqPCR. At the cytology of lizard blood, Leishmania spp. amastigote-like forms were detected in erythrocytes. Twenty-two tissue samples, mostly lung (21.4%), scored molecularly positive for L. tarentolae, corresponding to 10 lizards (i.e., 35.7%). Of the female Sergentomyia minuta sampled (n = 1252), 158 scored positive for L. tarentolae, four for L. infantum, and one co-infected. Two Phlebotomus perniciosus (out of 29 females) were positive for L. tarentolae. Engorged S. minuta (n = 10) fed on humans, and one P. perniciosus, positive for L. tarentolae, on lagomorphs.

Conclusions

Dogs and lacertid lizards (Podarcis siculus) were herein found for the first time infected by L. tarentolae. The detection of both L. tarentolae and L. infantum in S. minuta and P. perniciosus suggests their sympatric circulation, with a potential overlap in vertebrate hosts. The interactions between L. tarentolae and L. infantum should be further investigated in both vectors and vertebrate hosts to understand the potential implications for the diagnosis and control of canine leishmaniasis in endemic areas.

Graphical abstract

Cost-effectiveness of a canine visceral leishmaniasis control program in Brazil based on insecticide-impregnated collars

INTRODUCTION

The use of insecticide-impregnated dog collars is a potentially useful tool for the control of visceral leishmaniasis. The objective of the present study was to perform a cost-effectiveness analysis of a program based on insecticide-impregnated collars compared to traditional visceral leishmaniasis control strategies used in Brazil.

METHODS

A cost-effectiveness analysis was performed from the perspective of the Unified Health System, using data from the Visceral Leishmaniasis Control Program implemented in the municipality of Montes Claros, Minas Gerais. The direct costs of the three control strategies, which were 1) canine infection screening + sacrifice, 2) residual chemical control of the vector, and 3) insecticide-impregnated dog collars (Scalibor®), were evaluated over the two-year study period.

RESULTS

The total cost of the program in the area subjected to the traditional control strategies (strategies 1 and 2; control area) was R$ 1,551,699.80, and in the area subjected to all three control strategies (intervention area), it was R$ 1,898,190.16. The collar program was considered highly cost-effective at preventing canine visceral leishmaniasis (incremental cost-effectiveness ratio of approximately R$ 578 per avoided dog sacrifice).

CONCLUSIONS

These results provide support for the decision by the Brazilian Ministry of Health in 2019 to provide insecticide-impregnated collars for the control of canine visceral leishmaniasis in a pilot project.

Recent Advancements in the Control of Cat Fleas

Simple Summary

The cat flea Ctenocephalides felis felis is the most important pest of domesticated cats and dogs worldwide. This review covers the recent advancements in the control of cat fleas. Over the years, there has been an interest in using ecologically friendly approaches to control fleas. To date, no biological, natural, or cultural means have been discovered that mitigate flea infestations. The recent registration of novel topical and oral therapies promises a new revolution in the control of fleas and ticks and the diseases associated with them.

Abstract

With the advent of imidacloprid and fipronil spot-on treatments and the oral ingestion of lufenuron, the strategies and methods to control cat fleas dramatically changed during the last 25 years. New innovations and new chemistries have highlighted this progress. Control strategies are no longer based on the tripartite approach of treating the pet, the indoor environment, and outdoors. The ability of modern therapies to break the cat flea life cycle and prevent reproduction has allowed for the stand-alone treatments that are applied or given to the pet. In doing so, we have not only controlled the cat flea, but we have prevented or reduced the impact of many of the diseases associated with ectoparasites and endoparasites of cats and dogs. This review provides an update of newer and non-conventional approaches to control cat fleas.

Effectiveness of insecticide-impregnated dog collars in reducing incidence rate of canine visceral leishmaniasis: A systematic review and meta-analysis

Canines are proven reservoir hosts of Leishmania infantum, the causative agent of human zoonotic visceral leishmaniasis, and therefore domestic dogs play a central role in transmitting the disease to humans. Studies on the effect of insecticide-impregnated dog collars for controlling canine visceral leishmaniasis (CanL) have been increasing; however, meta-analysis has not been conducted. This study assessed the effectiveness of insecticide-impregnated dog collars for preventing CanL. We searched (PubMed, Web of Science, Scopus, Embase, Ovid Medline(R), and Cochrane library), from inception until 2 May 2020. Two authors independently performed articles screening and data extraction. We applied the RoB 2.0 tool to evaluate the risk of bias in randomized trials, while the ROBINS-I tool was used for non-randomized trials. I-squared statistics(I²) and funnel plot and Egger’s test, respectively, were used to assesses heterogeneity between studies and publication bias. Relative Risk (RR) and 95% Confidence Interval (CI) were calculated using the random-effects model in Stata 14 software. Out of 242 citations identified, 14 studies comprising 3786 collared dogs and 3428 uncollared dogs were eligible for meta-analysis. The use of deltamethrin-impregnated dog collars(DMC) showed an overall effectiveness of 54% (95%CI: 35–65%, I² = 63.2%, P = 0.002) in decreasing incidence of CanL, while 10% imidacloprid and 4.5% flumethrin collars provided an overall effectiveness of 90% (95%CI: 80–96%, I² = 0.0%, P = 0.376). DMC efficacy stratified by follow-up duration was estimated to be 58% (RR = 0.42, 95%CI: 0.20–0.87), 54% (RR = 0.46, 95%CI: 0.31–0.68), 53% (RR = 0.47, 95%CI: 0.29–0.82) for follow-up periods of 5 to 6 months, 1 year and 2 years, respectively. The current evidence indicates that using insecticide-impregnated dog collars can reduce the risk of CanL caused by L. infantum. Therefore, insecticide-impregnated dog collars could be a viable alternative for inclusion as a public health measure for controlling CanL.

Immunoprophylaxis pharmacotherapy against canine leishmaniosis: A systematic review and meta-analysis on the efficacy of vaccines approved in European Union

Leishmania (L.) infantum is a vector-borne parasite currently endemic in several Southern countries of European Union (EU), and dogs represent the main reservoir and hosts. Data from clinical trials are inconsistent with respect to the efficacy of vaccination against L. infantum infection. Therefore, a quantitative synthesis via pairwise meta-analysis was performed in agreement with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) to increase the strength of evidence and assess the real efficacy profile of vaccines against L. infantum currently approved in EU. Data obtained from 1,394 dogs were extracted from 10 studies. The overall analysis indicated that vaccination is significantly effective in protecting against L. infantum infection (RR 0.40, 95%CI 0.23-0.72; I² 70%; P < 0.01 vs. negative controls). The subset analysis performed by excluding the effect modifiers and by considering only the studies that assessed the efficacy of vaccines currently available in EU, indicated that CaniLeish® (RR 0.38, 95%CI 0.20-0.72; I² 0%), but not Letifend® (RR 0.43, 95%CI 0.15-1.22; I² 37%), significantly protected against L. infantum infection when compared to negative controls (P < 0.05). The number needed to treat analysis showed that 3.77 (95%CI 2.59-6.94) and 10.99 (95%CI 8.28-16.34) dogs had to be treated with CaniLeish® and Letifend®, respectively, to prevent one case of infection compared to negative controls. Vaccination is effective in protecting against the risk L. infantum infection, but further studies are needed to assess whether CaniLeish® and Letifend® are characterized by similar efficacy profile.

Effectiveness of insecticide-impregnated collars for the control of canine visceral leishmaniasis

Visceral leishmaniasis is a neglected tropical disease widely distributed worldwide. In Brazil, the control measures adopted in the last decades have not been able to prevent the spread of the disease. This study aimed to evaluate the effectiveness of a population-based intervention using 4% deltamethrin-impregnated dog collars on the incidence of canine visceral leishmaniasis. A community intervention study was carried out in two areas of the city of Montes Claros, State of Minas Gerais, Brazil. In the control area, the preventive measures recommended by the Brazilian Program for Surveillance and Control of Visceral Leishmaniasis were implemented (culling of infected dogs and vector control with residual insecticides). In the intervention area, deltamethrin-impregnated collars were fit to domiciled dogs, in addition to the above mentioned preventive measures. At the beginning of the study, a census survey was carried out among domiciled dogs to detect the prevalence of L. infantum infection. Dogs found seronegative at recruitment were longitudinally followed-up to evaluate the incidence of infection. Monitoring of canine infection (control and intervention areas) and replacement of collars (intervention area) occurred through sequential surveys at 12, 18, and 24 months after the initial survey. At each survey, dogs were tested, and the owner answered a questionnaire about the general characteristics of the animal. Multilevel logistic regression models were used to test the effect of collars on the risk of canine infection, with households considered as aggregation units. Associations were expressed as odds ratios (OR) and respective 95% confidence intervals (95%CI). The prevalence of infection in the initial survey was 9.7% and 9.9% in the intervention and control areas, respectively (p = 0.732). Among a total of 20,477 dogs participating in the study, 9,770 were seronegative at recruitment. The cumulative incidence of infection was 4.1% in the intervention area and 7.9% in the control area (p < 0.001). In the multivariable analysis, the risk of infection was 52% lower in the intervention area as compared to the control area (OR = 0.48, 95%CI:0.39-0.59), after adjusting for the number of dogs in the house, period of recruitment, time of dog ownership, and age, sex, length of fur and breed. The use of 4% deltamethrin-impregnated dog collars was effective in reducing the incidence of canine leishmaniasis. Cost-effectiveness studies are recommended before the incorporation of collars in the arsenal of control measures of the Brazilian Program for Surveillance and Control of Visceral Leishmaniasis.

How much does it cost to prevent and control visceral leishmaniasis in Brazil? Comparing different measures in dogs

Visceral leishmaniasis (VL) is an important zoonosis in Brazil. Dogs are considered the main domestic reservoirs of the disease in the country; hence, control measures are focused on these reservoirs. Despite efforts to prevent and control VL, important reductions in disease prevalence and incidence have not been identified, stimulating the development and application of new strategies. The choice and implementation of new control strategies can benefit from the application of mathematical models that allow the simulation of different strategies in different scenarios. Selecting the best strategy to be implemented is also supported by cost-effectiveness studies. Here we used the results of a mathematical model in which scenarios, including isolated use of the vaccine and insecticide-impregnated collar (IIC), both at different coverage rates, were simulated to conduct a cost-effectiveness study. The costs were calculated for each scenario considering a simulation period of four years. Collar application in both infected and non-infected animals was the most cost-effective strategy. For example, to reduce the prevalence in humans and dogs by approximately 70%, the costs ranged from $250,000 and $550,000 for the IICs and vaccination, respectively. Even in the scenario with 40% loss/replacement of IICs, this measure was more advantageous in terms of cost-effectiveness than vaccination. If the vaccine were applied with culling of seropositive tested dogs, then the measure became more effective with a reduced cost compared with the vaccine alone. The use of the three first consecutive vaccine doses had the greatest impact on the cost of the vaccination strategy. The advantage of using IICs is that there is no need for a prior diagnosis, unlike vaccination, reducing costs and facilitating implementation. The present study aims to contribute to strategies to reduce hosts infected with VL by reducing public expenditure.

Canine Leishmaniosis Control through the Promotion of Preventive Measures Appropriately Adopted by Citizens

Canine leishmaniosis (CanL) is a disease caused by the protist Leishmania infantum and transmitted to dogs by sand fly (Diptera: Phlebotominae) bites. In 2005, a new autochthonous focus of CanL was recognised in the southern part of Euganei hills (northeastern Italy). In subsequent years, this outbreak was monitored, testing dogs and evaluating sand fly population. Moreover, dog owners were sensitized on the adoption of preventive measures, thanks to the collaboration of local administration, health authorities, and private veterinarians. This study includes serological tests on dogs, questionnaires submitted to dog owners regarding the use of preventive measures on their animals, and the evaluation of sand fly abundance. Data collected were statistically compared with those of previous years. The canine seroprevalence was significantly lower than that recorded at the beginning of the outbreak, despite the fact that sand fly abundance did not significantly decrease. In addition, most of the dog owners declared using regularly the topical insecticides on their dogs during the sand fly season. This experience demonstrated that a collaborative approach among scientific researchers, local authorities, and private veterinarians can achieve excellent results in the management of a leishmaniosis outbreak.

Canine serological survey and dog culling ant its relationship with human visceral leishmaniasis in an endemic urban area

BACKGROUND

Visceral leishmaniasis is an important but neglected disease that is spreading and is highly lethal when left untreated. This study sought to measure the Leishmania infantum seroprevalence in dogs, the coverage of its control activities (identification of the canine reservoir by serological survey, dog culling and insecticide spraying) and to evaluate its relationship with the occurrence of the disease in humans in the municipalities of Araçatuba and Birigui, state of São Paulo, Brazil.

METHODS

Information from 2006 to 2015 was georeferenced for each municipality and modeling was performed for the two municipalities together. To do this, latent Gaussian Bayesian models with the incorporation of a spatio-temporal structure and Poisson distribution were used. The Besag-York-Mollie models were applied for random spatial effects, as also were autoregressive models of order 1 for random temporal effects. The modeling was performed using the INLA (Integrated Nested Laplace Approximations) deterministic approach, considering both the numbers of cases as well as the coverage paired year by year and lagged at one and two years.

RESULTS

Control activity coverage was observed to be generally low. The behavior of the temporal tendency in the human disease presented distinct patterns in the two municipalities, however, in both the tendency was to decline. The canine serological survey presented as a protective factor only in the two-year lag model.

CONCLUSIONS

The canine serological coverage, even at low intensity, carried out jointly with the culling of the positive dogs, suggested a decreasing effect on the occurrence of the disease in humans, whose effects would be seen two years after it was carried out.

Spatial and seroepidemiology of canine visceral leishmaniasis in an endemic Southeast Brazilian area

INTRODUCTION:

Canine visceral leishmaniasis (CVL) is a public health problem, and its prevalence is associated with the coexistence of vectors and reservoirs. CVL is a protozoonosis caused by Leishmania infantum that is endemic in the southeast region of Brazil. Thus, vector and canine reservoir control strategies are needed to reduce its burden. This study aimed to verify the CVL seroprevalence and epidemiology in a municipality in Southeast Brazil to initiate disease control strategies.

METHODS:

A total of 833 dogs were subjected to Dual Path Platform (DPP) testing and enzyme-linked immunosorbent assays. For seropositive dogs, epidemiological aspects were investigated using a questionnaire and a global position system. The data were submitted to simple logistic regression, kernel estimation, and Bernoulli spatial scan statistical analysis.

RESULTS:

The overall CVL-confirmed seroprevalence was 16.08%. The 28.93% in the DPP screening test was associated with dogs maintained in backyards with trees, shade, animal and/or bird feces, and contact with other dogs and cats, with sick dogs showing the highest chances of infection (odds ratio, 2.6; 95% confidence interval, 2.38-1.98), especially in residences with elderly people. A spatial analysis identified two hotspot regions and detected two clusters in the study area.

CONCLUSIONS:

Our results demonstrated that residences with elderly people and the presence of trees, shade, feces, and pet dogs and cats increased an individual’s risk of developing CVL. The major regions where preventive strategies for leishmaniasis were to be initiated in the endemic area were identified in two clusters.

Experimental assessment of permethrin-fipronil combination in preventing Leishmania infantum transmission to dogs under natural exposures

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Controlled experimental field study allowing natural exposure to sandflies.

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Two groups of 20 dogs each in two close sub-unit kennels.

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7/20 dogs infected by L. infantum in the untreated group.

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0/20 dogs infected by L. infantum in the fipronil-permethrin monthly treated group.

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100 % protection obtained during this one-year study.

Canine vector-borne disease transmission can be reduced with regular use of repellent insecticides. The objective of this year-long experimental study was to assess the efficacy of a topical formulation of fipronil/permethrin (Frontline Tri-Act®) in preventing transmission of Leishmania infantum by sandflies. This clinical field trial was conducted in Xanthi (Northern Greece), an area highly endemic for canine leishmaniosis, from April 2018 to March 2019. Forty purpose-bred Beagle dogs, testing negative for L. infantum prior to study initiation, were enrolled in the study, which consisted of three phases: Phase 1 (field exposure phase) took place from Day 0–196. The dogs were randomly allocated to two groups, group 1 (sham-treated topically with sterile water) and group 2 (treated topically with Frontline Tri-Act®). Dogs in both groups were housed in two subunits of an open-air kennel for a period of 7 months, spanning the Leishmania transmission season. All dogs were treated or sham-treated on Days 0, 28, 56, 84, 112, 140 and 168. Clinical examinations, PCR analysis of conjunctival swabs, and serological tests were performed on a monthly basis. Sandflies were collected every 2 weeks, during a 12 -h period overnight using light traps. Each collection was placed in a container and kept refrigerated until speciation and PCR analysis could be performed. In the second phase of the study, from Day 197 to 252, the dogs were moved into a protected environment (insect-proof protected environment phase). CDC light traps were activated every 2 weeks inside and outside the kennels to ensure the vector-free status of the facility. Monthly clinical examinations, including PCR analysis of conjunctival swabs, and serological tests continued. At the end of the phase 2, bone marrow samples were collected on all dogs. Phase 3 (the final post-winter check) took place from Day 253 to 350. Dogs were released and adopted by individual private owners on Day 253. Follow up analyses included blood collection for SNAP tests and conjunctival swaps for PCR analysis on Days 304 and 350. Additionally, bone marrow collections were also performed on Day 350.

Presence of sandflies was observed only in the phase 1 exposure period, and 1714 sandflies were collected (1427 females and 287 males). Two species were identified, Phlebotomus perniciosus var. tobbi and Phlebotomus neglectus. Out of the 62 pooled samples of sandflies assessed by PCR, three were considered positive (4.8 %). By the end of the study, 35 % of the Group 1 dogs (7/20) became positive based on PCR (conjunctival swab and bone marrow) and 30 % (6/20) based on SNAP/IFAT and ELISA tests, while all the dogs in the Frontline Tri-Act® treated group 2 remained negative for all tests (G1 vs G2, p = 0.008). All tests identified the same positive animals, and PCR allowed the detection of one additional infected dog. This clinical field trial demonstrated that monthly administration of Frontline Tri-Act® to dogs exposed to Leishsmania infection in a high endemic area provided 100 % preventive efficacy against transmission of L. infantum.

Evaluation of canine leishmaniosis vaccine CaniLeish® under field conditions in native dog populations from an endemic Mediterranean area-A randomized controlled trial

Dog vaccination is considered an effective way of reducing Leishmania infantum infection incidence in the canine population, as well as its transmission to humans. However, the use of partially effective vaccines can have the detrimental effect of "masking" vaccinated asymptomatic carriers, capable of harbouring the parasite and transmitting it to naïve individuals. After eight years on the European market, few studies have been released on CaniLeish® vaccine safety and efficacy. The present study, a one-year randomized CaniLeish® vaccine field trial, was performed in a canine leishmaniosis endemic area and included animals selected from a native dog population (n = 168). No severe adverse reactions were observed in vaccinated dogs (n = 85). Cases of active L. infantum infection were detected by serological, molecular and clinical follow-up of dogs. One-year post-vaccination, no differences in number or severity of L. infantum active infections were observed between study groups (n = 4 in each group). Vaccine-induced cellular immunity, assessed through interferon-γ quantification, showed significantly higher levels of this cytokine one-month post-vaccination in the vaccine group (p < 0.001), but no differences were observed after nine months between trial groups (p = 0.078). These results fail to support the reported CaniLeish® efficacy in the prevention of active L. infantum infection in dogs from endemic areas and naturally exposed to the parasite.

Identification of trypanosomatids and blood feeding preferences of phlebotomine sand fly species common in Sicily, Southern Italy

In this study, the presence of Leishmania DNA and blood feeding sources in phlebotomine sand fly species commonly present in Sicily were investigated. A total of 1,866 female sand flies including 176 blood fed specimens were sampled over two seasons in five selected sites in Sicily (southern Italy). Sergentomyia minuta (n = 1,264) and Phlebotomus perniciousus (n = 594) were the most abundant species at all the sites, while three other species from the genus Phlebotomus (i.e., P. sergenti n = 4, P. perfiliewi n = 3 and P. neglectus n = 1) were only sporadically captured. Twenty-eight out of the 1,866 (1.5%) sand flies tested positive for Leishmania spp. Leishmania tarentolae DNA was identified in 26 specimens of S. minuta, while the DNA of Leishmania donovani complex was detected in a single specimen each of S. minuta and P. perniciosus. Interestingly, seven S. minuta specimens (0.4%) tested positive for reptilian Trypanosoma sp. Blood sources were successfully identified in 108 out of 176 blood fed females. Twenty-seven out of 82 blood sources identified in fed females of P. perniciosus were represented by blood of wild rabbit, S. minuta mainly fed on humans (16/25), while the sole P. sergenti fed specimen took a blood meal on rat. Other vertebrate hosts including horse, goat, pig, dog, chicken, cow, cat and donkey were recognized as blood sources for P. perniciosus and S. minuta, and, surprisingly, no reptilian blood was identified in blood-fed S. minuta specimens. Results of this study agree with the well-known role of P. perniciosus as vector of L. infantum in the western Mediterranean; also, vector feeding preferences herein described support the hypothesis on the involvement of lagomorphs as sylvatic reservoirs of Leishmania. The detection of L. donovani complex in S. minuta, together with the anthropophilic feeding-behaviour herein observed, warrants further research to clarify the capacity of this species in the transmission of pathogens to humans and other animals.

Commercially approved vaccines for canine leishmaniosis: a review of available data on their safety and efficacy

Canine leishmaniosis is an important vector-borne zoonosis caused mainly by Leishmania infantum. Diagnosis and treatment of affected individuals can be particularly complex, hindering infection control in endemic areas. Methods to prevent canine leishmaniosis include the use of topical insecticides, prophylactic immunotherapy and vaccination. Four vaccines against canine leishmaniosis have been licensed since 2004, two in Brazil (Leishmune®, the production and marketing licence of which was withdrawn in 2014, and Leish-Tec®) and two in Europe (CaniLeish® and LetiFend®). After several years of marketing, doubts remain regarding vaccine efficacy and effectiveness, potential infectiousness of vaccinated and infected animals or the interference of vaccine-induced antibodies in L. infantum serological diagnosis. This review summarises the scientific evidence for each of the vaccines commercially approved for canine leishmaniosis, while discussing possible weaknesses of these studies. Furthermore, it raises the need to address important questions related to vaccination impact in Leishmania-endemic countries and the importance of post-marketing pharmacological surveillance.

Vaccination against canine leishmaniasis in Brazil

Prevention of canine Leishmania infantum infection is critical to management of visceral leishmaniasis in people living in endemic areas of Brazil. A bill (PL 1738/11), currently under consideration, proposes to establish a national vaccination policy against canine leishmaniasis in Brazil. However, there is no solid scientific evidence supporting the idea that this could reduce transmission from infected vaccinated dogs to sand flies to a level that would significantly reduce the risk of L. infantum infection or visceral leishmaniasis in humans. Thus, we advocate that insecticide-impregnated collars should the first line protective measure for public health purposes and that vaccines are applied on a case-by-case, optional basis for individual dog protection.

Leishmania infantum in wild animals in endemic areas of southern Italy

Leishmania infantum infection in wildlife is increasingly reported in Europe, but scant data are available in Italy so far. This study aimed to investigate the circulation of L. infantum among sylvatic hosts in Sicily (southern Italy), a highly endemic area for canine leishmaniosis, through serological and molecular tools. Target tissues (skin, spleen, lymph nodes) collected from 71 European rabbits, 2 European hares, 7 red foxes, 11 European wildcats and 1 pine marten, were qPCR analysed for the detection of L. infantum DNA. Additionally, 40 rabbits, older than one year, were serologically screened for specific anti-Leishmania antibodies. Leishmania infantum was molecularly diagnosed in 5.4% (n = 5) of the examined animals (3/71 European rabbits, 2/7 red foxes). In many of the qPCR positive animals (4/5), the parasite DNA was more prevalent in visceral than cutaneous tissues. None of the positive animal showed signs of disease and/or macroscopic alterations of organs; low parasitic burden in all positive tissue samples was also recorded. Only one rabbit serum (i.e., 2.5%) tested positive for anti-Leishmania antibodies. The seropositive rabbit was in good health status and no amastigotes were observed in lymph-node aspirate and blood smears. This study provides first evidence of L. infantum infection in wild animals from Sicily (southern Italy). Despite the low prevalence of infection here reported, the circulation of the Leishmania in wild reservoirs in Sicily remains worthy of future investigations for a better understanding of their role in the epidemiology of the disease as well as to fine-tune control strategies in the area.

Effectiveness of the mass use of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis by Lutzomyia spp.: A cluster randomized controlled trial

Visceral leishmaniasis (VL) is a zoonosis that greatly impacts public health, especially in developing countries. The effectiveness of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis (CanL) by the sand fly Lutzomyia spp. in countries with high incidence of the disease, such as Brazil, remains unknown. A cluster randomized controlled trial was carried out to evaluate the effectiveness of these collars in preventing infection of dogs with Leishmania infantum. Two areas were selected in a municipality endemic for VL in Brazil: an experimental area (EA) and a control area (CA). In both areas, blood samples were collected from dogs for detection of CanL. Seronegative dogs from the EA received collars impregnated with deltamethrin 4%. After six months, the dogs were retested for CanL and the incidence of the disease, the relative risk, and the effectiveness of collaring determined. In the baseline survey, 1020 dogs from the EA and 589 from the CA were examined. The prevalence calculated for EA was 4.41% (CI95% 3.27-5.91), and 7.13% (CI95% 5.25-9.59) for CA. In the second evaluation, 454 dogs from the EA and 292 from the CA were examined. The person-time incidence calculated for EA was 3.51% (CI95% 1.30-7.48), and for CA was 11.81% (CI95% 7.03-18.23). The difference between the calculated incidences was statistically significant (p = 0.009). The relative risk was 0.2972 (CI95% 0.1204-0.7339; p = 0.009), and the efficacy of the proposed measure was estimated in 70.27%. This report evaluated the effectiveness of the mass use of deltamethrin-impregnated dog collars in areas of transmission of VL by Lutzomyia spp. Collaring was able to protect dogs and may represent an effective strategy that could be implemented to control infection in both dogs and humans in Brazil and perhaps other countries where Lutzomyia spp. is the main vector of the disease.

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

In the present study, we assessed the annual screening coverage (i.e., the percentage of dogs that are screened for anti-Leishmania antibodies annually) in the municipality of Sobral, Ceará state, Brazil. Data on the number of dogs screened during 2008−2017 (except 2010) were obtained from the Centre for Zoonoses Control of Sobral. The annual screening coverage during 2012−2017 was calculated. Data on human visceral leishmaniasis (VL) cases during 2008−2017 were compiled from the National Disease Notification System. Correlation analyses were performed to assess the correlation between canine and human data. During 2008−2017, 73,964 dogs (range, 0 to 13,980 dogs/year) were serologically screened and 2,833 (3.8%) were positive. The annual screening coverage during 2012−2017 ranged from 11.1% to 45.7%. There were no significant correlations between the number of dogs culled and the number of human VL cases, canine positivity and human VL incidence, number of dogs culled and human VL incidence, or between canine positivity and number of human VL cases. An inconsistent and relatively low annual screening coverage was found in the study area, with no dog being screened in 2010 due to the lack of serological tests. Our results highlight that many dogs potentially infected with Leishmania infantum have been virtually overlooked by public health workers in the study area, perhaps with a negative, yet underestimated, impact on the control of canine and human VL. Hence, the failure of the dog culling strategy in controlling human VL in Brazil may be due to the low screening coverage and low percentage of culled dogs, rather than the absence of associations between canine and human infections.

The euthanasia of Leishmania-seropositive dogs has been recommended for controlling human visceral leishmaniasis (VL) in some countries where this zoonosis is endemic. We assessed the annual screening coverage (i.e., the percentage of dogs living in a given area that are screened for anti-Leishmania antibodies annually) in the municipality of Sobral, Ceará state, one of the main foci of human VL in Brazil. From 2008 to 2017, nearly 74,000 dogs were screened and 3.8% of them were positive for anti-Leishmania antibodies. No statistically significant correlation was found between the number of dogs culled annually and the incidence of human VL. The annual screening coverage ranged from 11.1% to 45.7%. Our results highlight an inconsistent and relatively low annual screening coverage, indicating that dogs potentially infected with L. infantum have been virtually overlooked by public health workers in the study area.

Insecticide-impregnated dog collars reduce infantile clinical visceral leishmaniasis under operational conditions in NW Iran: A community-wide cluster randomised trial

OBJECTIVE

To assess the effectiveness of community-wide deployment of insecticide-impregnated collars for dogs- the reservoir of Leishmania infantum-to reduce infantile clinical visceral leishmaniasis (VL).

METHODS

A pair matched-cluster randomised controlled trial involving 40 collared and 40 uncollared control villages (161 [95% C.L.s: 136, 187] children per cluster), was designed to detect a 55% reduction in 48 month confirmed VL case incidence. The intervention study was designed by the authors, but implemented by the Leishmaniasis Control Program in NW Iran, from 2002 to 2006.

RESULTS

The collars provided 50% (95% C.I. 17·8%-70·0%) protection against infantile VL incidence (0·95/1000/yr compared to 1·75/1000/yr). Reductions in incidence were observed across 76% (22/29) of collared villages compared to pair-matched control villages, with 31 fewer cases by the end of the trial period. In 11 paired villages, no further cases were recorded post-intervention, whereas in 7 collared villages there were 9 new clinical cases relative to controls. Over the trial period, 6,835 collars were fitted at the beginning of the 4 month sand fly season, of which 6.9% (95% C.I. 6.25%, 7.56%) were lost but rapidly replaced. Collar coverage (percent dogs collared) per village varied between 66% and 100%, with a mean annual coverage of 87% (95% C.I. 84·2, 89·0%). The variation in post-intervention clinical VL incidence was not associated with collar coverage, dog population size, implementation logistics, dog owner compliance, or other demographic variables tested. Larger reductions and greater persistence in incident case numbers (indicative of transmission) were observed in villages with higher pre-existing VL case incidence.

CONCLUSION

Community-wide deployment of collars can provide a significant level of protection against infantile clinical VL, achieved in this study by the local VL Control Program, demonstrating attributes desirable of a sustainable public health program. The effectiveness is not dissimilar to the community-level protection provided against human and canine infection with L. infantum.

Effectiveness of deltamethrin-impregnated dog collars on the incidence of canine infection by Leishmania infantum: A large scale intervention study in an endemic area in Brazil

To reduce morbidity and mortality caused by visceral leishmaniasis (VL), the Brazilian Visceral Leishmaniasis Control and Surveillance Program promotes the diagnosis and treatment of cases, vector control, euthanasia of seropositive dogs, and health education. Nevertheless, the effectiveness of these measures is questionable as they lead to little reduction in the transmission of the disease. Thus, the effectiveness of strategies such as insecticide-impregnated collars, spot-on insecticides, and immunization of dogs should be assessed. Herein, we evaluated the effectiveness of deltamethrin-impregnated collars on reducing the incidence of Leishmania infantum infection in dogs living in an endemic area of VL. An intervention study was conducted and a total 5,850 dogs were analyzed in baseline. Of these 3,742 seronegative dogs were divided into two groups: collared and uncollared (control). Dogs were followed for 12 months and three interventions were performed. The Cox regression model was used to evaluate the effectiveness of the collar. All analyzes were performed by Intention-to-treat and per-protocol. By intention-to-treat, the incidence rates of L. infantum infection were 7.5 and 7.9 in the collar group, and 6.5 and 13.2 per 1,000 dogs-months in the control group after 6 and 12 months, respectively. In the per-protocol analysis, the incidence rates in the control group were similar to those observed in the intention-to-treat analysis. In the collar group, the incidence rate was 5.1/1,000 dogs-months after 6 and 12 months. The effectiveness by intention-to-treat after adjustment by the multivariate Cox model was 48%. In the analysis per-protocol, the effectiveness increased to 63%. Although collar use was effective when it was evaluated by intention-to-treat, higher effectiveness was found in the per-protocol analysis after one year of follow-up. The data emphasize the importance of the uninterrupted use of deltamethrin-impregnated collars to increase protection against canine VL.

Controlling phlebotomine sand flies to prevent canine Leishmania infantum infection: A case of knowing your enemy

Leishmaniosis caused by Leishmania infantum is a widespread zoonotic disease that can be transmitted to animals and humans by their vectors, blood-sucking phlebotomine sand flies. To prevent canine leishmaniosis across the whole Mediterranean region, vector control is essential. Because of phlebotomine breeding sites are diverse, environmental larval controls have limited practical value. Control methods of adults are being evaluated, such as selective baits based on sugar feeding of males and females or Attractive Toxic Sugar Baits (ATSB), and the indoor use of Long-Lasting-Insecticidal Nets (LLINs) treated with permethrin to prevent sand fly bites complementing the Indoor Residual Spraying (IRS) approach suggested by WHO. Although several strategies exist, the best control measure to prevent canine Leishmania infantum is to treat dogs using biocidal topical formulations based on legal insecticides (PTs18) or repellents (PTs19) (as collars, spot-ons and/or sprays) during the period when the vectors are active. This means we need to really know the biology and life cycle of the sand fly vector. According to available data, by mapping ambient temperatures we can already predict high risk areas where vector densities will be higher. In ongoing research, new candidates are emerging to fight against sand flies including natural plant extracts with low impacts on the environment and host animal. Other options in the future could be systemic insecticides to help reduce sand fly populations in high density areas. In parallel, health authorities and professionals involved in animal and public health (veterinarians, physicians, entomologists and epidemiologists) must work together in a One Health approach to minimize Leishmania infection. Veterinarians play a crucial role in liaising between key stake holders and dog owners to ensure the latter act responsibly in using repellents as a preventive measure against sand fly bites.

Canine Leishmaniasis: An Overview of the Current Status and Strategies for Control

Canine leishmaniasis (CanL) is a vector-borne disease caused by Leishmania infantum and is transmitted by female phlebotomine sand flies primarily between animals and secondarily to humans. The course of infection may be different from one individual dog to another, ranging from spontaneous cure to acute evolution that leads to death, if proper management and therapy are not adopted. A parasitological cure is rarely achieved and clinical recurrences in CanL are frequent. Vaccination associated with the use of topical insecticides is undoubtedly the most effective form of prevention and control of the disease. In order to integrate the most important scientific knowledge of the literature in one objective publication, this review proposes a short overview of the main points of CanL.

Vaccine effectiveness and use of collar impregnated with insecticide for reducing incidence of Leishmania infection in dogs in an endemic region for visceral leishmaniasis, in Brazil

Although a national programme for control of visceral leishmaniosis (VL) is being run in Brazil, the disease continues to spread. This programme is essentially based on culling infected dogs from endemic regions. Thus, there is an urgent need to develop other control measures against VL to deter its advance. Here, a subunit vaccine, a recombinant vaccine, an insecticide-impregnated collar and the associations between these measures were evaluated for reducing the incidence of Leishmania infection in dogs. This was through a cohort study conducted in an endemic region of Brazil, considering the incidence and time of total exposure over a period of 1 year. The incidence of VL was estimated by means of serological and molecular diagnostic tests, 180 and 360 days after the application of the control measures. The estimates of the effectiveness (EF) were not significant in any cohort. The EF of the subunit vaccine, the recombinant vaccine and the collar were 26.4%, 32.8% and 57.7% and the upper limit of the 95% confidence interval for EF were 63.7%, 67.9% and 82.5%, respectively. In conclusion, under the conditions of this study, none of the immunogens for VL control was sufficiently effective to protect dogs against infection. On the other hand, use of collars impregnated with insecticide seems to constitute a method with better prognosis, corroborating other studies in this field.

Drug resistance in protozoan parasites

As with all other anti-infectives (antibiotics, anti-viral drugs, and anthelminthics), the limited arsenal of anti-protozoal drugs is being depleted by a combination of two factors: increasing drug resistance and the failure to replace old and often shamefully inadequate drugs, including those compromised by (cross)-resistance, through the development of new anti-parasitics. Both factors are equally to blame: a leaking bathtub may have plenty of water if the tap is left open; if not, it will soon be empty. Here, I will reflect on the factors that contribute to the drug resistance emergency that is unfolding around us, specifically resistance in protozoan parasites.

The Biology and Ecology of Cat Fleas and Advancements in Their Pest Management: A Review

The cat flea Ctenocephalides felis felis (Bouché) is the most important ectoparasite of domestic cats and dogs worldwide. It has been two decades since the last comprehensive review concerning the biology and ecology of C. f. felis and its management. Since then there have been major advances in our understanding of the diseases associated with C. f. felis and their implications for humans and their pets. Two rickettsial diseases, flea-borne spotted fever and murine typhus, have been identified in domestic animal populations and cat fleas. Cat fleas are the primary vector of Bartonella henselae (cat scratch fever) with the spread of the bacteria when flea feces are scratched in to bites or wounds. Flea allergic dermatitis (FAD) common in dogs and cats has been successfully treated and tapeworm infestations prevented with a number of new products being used to control fleas. There has been a continuous development of new products with novel chemistries that have focused on increased convenience and the control of fleas and other arthropod ectoparasites. The possibility of feral animals serving as potential reservoirs for flea infestations has taken on additional importance because of the lack of effective environmental controls in recent years. Physiological insecticide resistance in C. f. felis continues to be of concern, especially because pyrethroid resistance now appears to be more widespread. In spite of their broad use since 1994, there is little evidence that resistance has developed to many of the on-animal or oral treatments such as fipronil, imidacloprid or lufenuron. Reports of the perceived lack of performance of some of the new on-animal therapies have been attributed to compliance issues and their misuse. Consequentially, there is a continuing need for consumer awareness of products registered for cats and dogs and their safety.

Field evaluation of a new light trap for phlebotomine sand flies

Light traps are one of the most common attractive method for the collection of nocturnal insects. Although light traps are generally referred to as "CDC light traps", different models, equipped with incandescent or UV lamps, have been developed. A new light trap, named Laika trap 3.0, equipped with LED lamps and featured with a light and handy design, has been recently proposed into the market. In this study we tested and compared the capture performances of this new trap with those of a classical light trap model under field conditions. From May to November 2013, a Laika trap and a classical light trap were placed biweekly in an area endemic for sand flies. A total of 256 sand fly specimens, belonging to 3 species (Sergentomyia minuta, Phlebotomus perniciosus, Phlebotomus neglectus) were collected during the study period. The Laika trap captured 126 phlebotomine sand flies: P. perniciosus (n=38); S. minuta (n=88), a similar number of specimens (130) and the same species were captured by classical light trap which collected also 3 specimens of P. neglectus. No significant differences in the capture efficiency at each day of trapping, neither in the number of species or in the sex of sand flies were observed. According to results of this study, the Laika trap may be a valid alternative to classical light trap models especially when handy design and low power consumption are key factors in field studies.

Prevention of feline leishmaniosis with an imidacloprid 10%/flumethrin 4.5% polymer matrix collar

Background

Leishmaniosis caused by Leishmania infantum is one of the most important vector-borne diseases affecting animals and humans worldwide. Dogs are considered main reservoirs of the zoonotic forms, though in the last years the role of cats as reservoirs has been increasingly investigated. Feline leishmaniosis (FeL) occurs in endemic areas and no specific preventive measures have been investigated so far. In this study the efficacy of a 10% imidacloprid/4.5% flumethrin polymer matrix collar, licensed for tick and flea prevention, has been assessed against FeL in a longitudinal study on 204 privately owned cats from the Aeolian islands (Sicily), an area highly endemic for the disease. From March to May 2015 [Study Day 0 (SD 0)], cats negative for FeL were collared (G1, n = 104) or left untreated (G2, n = 100). Diagnosis consisted of serology and qPCR on blood and conjunctival swabs, which were collected at baseline (SD 0) and at the end of the study (SD 360). Interim clinical examinations were performed on SD 210 (when collars were replaced in G1) and SD 270.

Results

Of the 159 cats which completed the study, 5 in G1 and 20 in G2 were positive for L. infantum infection, in at least one of the diagnostic tests leading to a yearly crude incidence of 6.3% and 25.0% in G1 and G2, respectively (P = 0.0026). This translates into an efficacy of the collar of 75.0% in preventing feline Leishmania infection. The collar was generally well tolerated with no systemic adverse reactions and few local skin reactions were observed in the application area in four out of 104 treated cats (3.8%).

Conclusions

The 10% imidacloprid/4.5% flumethrin collar significantly reduced the risk of L. infantum infection in cats. To our knowledge, this is the first study in which a preventative strategy against feline Leishmania infection is assessed under natural conditions. These findings close a gap in veterinary medicine, in that they confirm this collar as a tool in reducing the risk of Leishmania infection in cats. Such a preventative tool could contribute to the reduction of the risk of the disease in animal and in human populations when included in integrated leishmaniosis control programmes.