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PURPOSE: This study determined the diversity and distribution of tick species infesting domestic dogs and the life cycle parameters of the dominant dog tick species. METHODS: An island-wide, cross-sectional survey of tick species infesting domestic dogs was carried out, and the life cycle of the most commonly occurring dog tick, Rhipicephalus sanguineus was studied under laboratory conditions. RESULTS: A total of 3026 ticks were collected from 1219 dogs in all 25 districts. Eight species in five genera were identified: R. sanguineus (63.4%), R. haemaphysaloides (22.0%), Haemaphysalis bispinosa (12.5%), Haemaphysalis intermedia (0.9%), Haemaphysalis turturis (0.6%), Amblyomma integrum (0.4%), Dermacentor auratus (0.2%) and Hyalomma sp (0.1%). R. sanguineus was the dominant species in the Dry and Wet zones, while R. haemaphysaloides was the dominant species in the Intermediate Zone. Species diversity (Shannon diversity index H) was 1.135, 1.021and 0.849 in the Intermediate, Dry and Wet zones, respectively. The three-host life cycle of R. sanguineus was completed within 70-126 days, and all three stages successfully fed on New Zealand white rabbits under laboratory conditions. The Reproductive Efficiency Index (REI) and Reproductive Fitness Index (RFI) were 50.8 ± 9.69 and 9.1 ± 5.01, respectively. Larger females had higher reproductive success. CONCLUSIONS: Of the eight species infesting domestic dogs in Sri Lanka, R. sanguineaus was the most frequently occurring tick species. The three-host life cycle of R. sanguineus was successfully completed within an average of 98 days on New Zealand white rabbits. The number of eggs laid, duration of the pre-oviposition period, incubation period and parasitic periods of all three life stages were lower than in previous records.

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PURPOSE: Babesiosis is one of the most important globally extended and quickly spreading tick-borne infections of dogs. Diagnosis of babesiosis in Sri Lanka is based on clinical signs followed by thin blood smears which could be error-prone due to undetected early infections, absence of clinical signs or low parasitemia. The present study investigated the prevalence of babesiosis in dogs presented to the Veterinary Teaching Hospital (VTH) at the Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, for treatments, vaccinations, and regular check-ups, and compared the diagnosis methods of microscopy and molecular analysis. METHODS: Blood samples from dogs were collected from January to June 2019. First, Giemsa stained blood smears were prepared, and then the blood samples were subjected to PCR using genus-specific primers to amplify a 411-450 bp region in the 18S rRNA gene. Twenty samples from PCR amplified products were sequenced for species identification and phylogenetic analysis. Clinical signs of the dogs were noted down, and ticks were also collected from dogs if any. RESULTS: Results show a very high prevalence of canine babesiosis (78.6%) among the dogs brought to the VTH. The parasite was identified microscopically and genetically as Babesia gibsoni. A large percentage (66.7%) of infections was asymptomatic. Out of 42 blood samples, 19 (45.2%) were microscopically positive for babesiosis while 33 (78.6%) were PCR positive, showing a significant difference in the two methods of diagnosis (chi-square test, χ2 = 9.462, p = 0.002). Three tick species: Rhipicephalus haemaphysaloides, Haemaphysalis bispinosa, and Rhipicephalus sanguineus were found attached to the dogs. CONCLUSION: This study shows a very high prevalence of canine babesiosis among dogs in the Kandy area. Most of these infections might go undetected if only microscopy was used to diagnose. An improved, rapid diagnostic method such as the novel, PCR-based point-of-care diagnostic method that detects very low parasitemia within 30 min is needed. Moreover, as most infected dogs did not show clinical signs, they may act as reservoirs of infection. The ability of asymptomatic dogs to spread babesiosis should be investigated.

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This study provides the first analysis and quantification of MPs in salt products in Sri Lanka. Commercial table salt brands, rock salt, lab-grade NaCl and raw salt from three salterns were analysed using microscopy and Fourier transform infrared spectroscopy. All salt samples were contaminated with MPs: in commercial salts products it ranged from 11 to 193 items/kg, rock salts had 64 items/kg and lab grade NaCl had 253 ± 8.9 items/kg. The MP levels in salterns varied significantly: Hambantota 3345.7 ± 311.4 items/kg, Puttalam 272.3 ± 10.6 items/kg, and Elephant Pass 36.3 ± 4.5 items/kg. Predominantly, MPs were presented as fibres, followed by fragments. Of the 23 polymer types identified; low-density polyethylene (LDPE; 17%), resin dispersion (15%) and high-density polyethylene (HDPE; 12%) were notable. This study provides the first comparison of MPs in raw salt and commercial salt. This information is important to trace the pollutant sources and then to take steps to eliminate MPs in food products consumed.

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PURPOSE: Otoacariasis is a parasitic otopathy reported in many parts of the world. This study presents the seasonal pattern, risk factors, and case notes on human otoacariasis in two climatically different districts: Anuradhapura and Kandy in the Dry and Wet/Intermediate zone of Sri Lanka, respectively. METHODS: Ticks removed from the ear canal of patients were collected. Risk factors of otoacarisis were determined by a case/control follow-up study. RESULTS: Nymphal Dermacentor auratus (90.8%) was the main tick species associated otoacariasis. In the Kandy District, infestation was year-round, while in the Anuradhapura District, it was seasonal with a peak in December-February. Children < 10 years were a risk group in both districts. Females were a risk group in the Kandy District. Engagement in outdoor activities was a risk factor in both districts. In addition, the presence of wildlife and domesticated animals were risk factors in the Kandy and Anuradhapura districts, respectively. The treatment protocols in the two hospitals were different. An infant with otoacariasis from the Anuradhapura District developed rickettsia. CONCLUSIONS: Although the tick species was the same, seasonality, risk groups, and risk factors in the two districts were different which could be due to the establishment and persistence of tick populations influenced by biotic and abiotic factors.

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Here we report three cases of canine trypanosomosis presented to the Veterinary Teaching Hospital in the Faculty of Veterinary Medicine and Animal Sciences at the University of Peradeniya, Sri Lanka during 2018. The cases were presented to the hospital when the dogs were already in critical condition. Confirmation of the cases was done by microscopic examination of Giemsa-stained thin blood smears. All three dogs had bilateral keratitis and anterior chamber cloudiness in eyes. Despite the intramuscular administration of diminazine aceturate, all of them subsequently died. Amplification and sequencing of a fragment of the internal transcribed spacer 1 (ITS1) of the nuclear ribosomal DNA confirmed the parasite as Trypanosoma. evansi. This is the first record of clinical cases of canine trypanosomosis in Sri Lanka. The three cases reported here came from widely separated geographical locations within the country: Balangoda, Mullaitivu and Kadawatha.

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Rhipicephalus haemaphysaloides Supino, 1897 (Ixodida: Ixodidae) is a three-host hard tick widely distributed in Sri Lanka. The lifecycle of the R. haemaphysaloides population in Sri Lanka was studied under laboratory conditions using fully engorged females collected from dogs. Larvae, nymphs and adults were reared on New Zealand rabbits. Engorged females weighed a mean ± standard deviation (SD) of 470.1 ± 106.5 mg and laid a mean ± SD of 4067.4 ± 3136.2 eggs within 16.1 ± 3.7 days. The mean ± SD preoviposition period was 6.5 ± 1.1 days. The mean ± SD reproductive efficiency index was 8.5 ± 4.1, and was higher in heavier females (Pearson correlation, r = 0.8; P = 0.001). The incubation period of eggs was shorter at higher temperatures. The majority (86.9%) of larvae successfully moulted after a mean ± SD premoulting period of 7.9 ± 0.7 days following a parasitic period of 3.2 ± 0.5 days. Unfed larvae survived a mean ± SD of 103.4 ± 19.8 days. Nymphs completed the bloodmeal after 3.7 ± 0.9 days, weighed 5.7 ± 1.7 mg and demonstrated a premoulting period of 15.1 ± 1.9 days. Unfed nymphs survived a mean ± SD of 45.8 ± 3.8 days. Heavier nymphs moulted into females, whereas lighter nymphs moulted into males (two-sample t-test, P < 0.001). The bodyweight of adult females increased more than 100-fold after feeding. The lifecycle of R. haemaphysaloides was successfully completed on rabbits within a mean of 91.3 days (range: 69-117 days) under laboratory conditions.

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Otobius megnini infests mainly domesticated and wild animals and occasionally humans. It has been identified as an agent of human and horse otoacariasis in Sri Lanka. The number of nymphal stages in the life cycle of O. megnini varies from one to three in different geographic regions. The present study determined the life cycle of O. megnini infesting the racehorses in Nuwara Eliya. A tick colony was initiated from fully engorged nymphs collected from horses and maintained at 10°C, 22°C and 28°C. Immature stages were reared on New Zealand rabbits. Only the larvae weighing more than 0.9mg (84.9%) moulted to nymphs with a pre-moulting period of 5.6(±1.7) days. None of the larvae maintained at 10±1°C moulted. Larval survival was significantly higher at 28±1°C (44.2±4.3days) than at 22±1°C (35.6±9days). At 28±1°C, majority of nymphs (95.6%) weighing over 10mg moulted into adults within 12.5(±3.1) days. Nymphs kept at 10±1°C underwent diapause for 81.1(±72.0) days. Larger females (>13mg; 93.0%) laid eggs for of 44.6(±17.8) days with a mean pre-oviposition period of 10.3(±5.1) days. Females survived longer (369.8±128.3days) than males (210.4±54.1days; Student's t-test; t=5.9, p=0.001). Some females laid eggs without mating. Otobius megnini successfully completed the life cycle within 123days and has only one nymphal instar similar to the Neotropical population. Currently, O. megnini infestation is a serious problem to horses in the Nuwara Eliya racecourse and may pose a risk of spreading to dairy farms close by owing to its dynamic nature of the life cycle.

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Tick infestation in humans is a major public health concern. The diversity and distribution of tick species associated with human otoacariasis was studied in five districts: Anuradhapura, Kandy, Kurunegala, Nuwara Eliya and Ratnapura in the main agro-climatic zones of Sri Lanka. Ticks from patients attending the ear, nose and throat clinics of the General Hospitals were collected during a 3 year period. In total 426 ticks were collected. Most human otoacariasis cases were reported from Kandy (33.8 %) and the fewest from Nuwara Eliya (8.2 %). Of the five tick species identified, nymphs of Dermacentor auratus constituted 90.6 % of the collection. Rhipicephalus sanguineus, Hyalomma isaaci, Haemaphysalis bispinosa and Otobius megnini were found rarely infesting humans possibly as an accidental host; H. bispinosa and O. megnini in the human ear canal were first time records in Sri Lanka. Females and children under 10 years were identified as risk groups of human otoacariasis. Subsequently, a field study was carried out to determine socio-ecological risk factors of human tick infestations in the five districts. Based on hospital data, eight villages with high prevalence of otoacariasis were selected from each district. A total 40 villages were visited and 1674 household members were interviewed. Involvement in outdoor activities, presence of wild animals around the house, location of the house in close proximity to a forest and occupation were identified as major risk factors.

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Amblyomma integrum Karsch, 1879 (Acari: Ixodidae) is one of four Amblyomma Koch, 1844 species with eyes found in southern India and Sri Lanka. The immature stages of this species were poorly described. Therefore, accurate identification is difficult. Here we re-describe the male, female, nymph and larva of A. integrum and illustrate all the stages in greater detail for the first time. A set of diagnostic morphological characters is defined to distinguish this species from other sympatric species of eyed Amblyomma in any parasitic stage of development. Adults of A. integrum parasitize mostly various larger mammals whereas nymphs and larvae use mostly larger and medium mammals. Amblyomma integrum is recorded from India (Andhra Pradesh, Goa, Karnataka, Orissa and Tamil Nadu States) and throughout Sri Lanka.

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Amblyomma integrum is a hard tick infesting mainly buffalo and cattle and has been identified as an agent of human otoacariasis in Sri Lanka. Data on the life cycle pattern of A. integrum were collected by experimental infestation on New Zealand white rabbits under laboratory conditions. Wild-caught females laid 55-7389 eggs for 2-35 days after spending a latent period of 10-25 days. Egg incubation period was 31-105 days and the newly emerged larvae started feeding after 4-11 days. Larvae dropped off after feeding and they moulted into nymphs after 10-16 days. Nymphs actively fed on rabbits for 4-8 days and dropped off. Engorged nymphs took 11-25 days for moulting before emerging as adults. The male:female sex ratio of the adults moulted under laboratory conditions was 11:9. All the stages showed periodicity in engorgement and dropping off. The three-host life cycle was completed within 74-245 days with an average of 152.9 days. The mean Reproductive Efficiency Index (REI) and Reproductive Aptitude Index (RAI) were 3.6 and 1.1, respectively. Females hatched in the laboratory did not successfully feed on New Zealand white rabbits. The wild-caught females which fed on buffaloes had prolonged pre-oviposition and oviposition periods, low REI, low RAI and low eclosion under controlled laboratory conditions compared to other tick species. Although larva and nymphs of A. integrum successfully fed on New Zealand white rabbits under laboratory conditions, full life cycle was not completed because the adult females did not feed on rabbits.

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Otobius megnini is a one host, nidicolous soft tick (Family Argasidae) whose larvae and nymphs parasitize the external ear canal of many wild and domestic animals and occasionally humans. The present study was conducted to determine the seasonal dynamics of O. megnini infesting stabled horses in Nuwara Eliya racecourses. Ticks were sampled biweekly for two years from May 2013 to May 2015 from the ear canal of seven thoroughbred male horses. Weather data: temperature, rainfall and humidity for the study period were obtained from the Meteorological Department, Colombo. A total of 23, 287 ticks of O. megnini were collected from the ear canal of horses and all of which were immature stages comprising 41.4% larvae and 59.6% nymphs. Larval counts were high during warmer months of the year with minimum numbers recording September-November. High larval abundance may be due to the high hatching rate of eggs at high temperatures. Larval abundance was significantly affected by maximum temperature, minimum relative humidity and average relative humidity (Multiple regression; r(2)=0.5, F=3.7, p=0.01). Population peaks for nymphs occurred in May, October and January. Nymph counts were low in March and April. Weather conditions did not have any correlation with the abundance of nymphs. Rainfall had no effect on both larvae and nymph counts. Even though control measures have been taken, O. megnini infestation is a serious problem for the stable owners especially because these horses are used in racing and other recreational purposes. Further, there is a high risk of spreading this tick within the country due to the presence of suitable hosts and the adaptability of the tick to survive in changing climatic conditions. Information on the seasonal dynamics of the tick population is important for employing control measures.

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Nosomma monstrosum (Nuttall & Warburton) is a hard tick infesting mainly buffalo and cattle in Sri Lanka. Biological data on the life cycle pattern of N. monstrosum were collected using experimental infestation on New Zealand white rabbits under laboratory conditions. The three-host life cycle was completed within 64-102 days. Eggs hatched after 20-29 days of incubation and the larvae hatched out started feeding which lasted for 2-4 days. After a moulting period of 8-11 days nymphs emerge and they actively fed for 2-4 days. Subsequently the nymphs took 15-18 days for moulting before emerging as adults. Freshly moulted females fed for 7-8 days and remained latent for 4-5 days before starting the oviposition. Females laid 3864-12,520 eggs for 11-17 days. The male: female sex ratio was 8:3 in the adults which were moulted under laboratory conditions. Strong positive correlations were found in female weight with number of eggs laid and REI. Females raised from the first generation of eggs had higher oviposition periods, higher REI, laid ten times more eggs, and lower pre-oviposition periods compared to those collected from the wild. When a suitable host is given, N. monstrosum could successfully complete its three-host life cycle under laboratory conditions.

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Megaselia scalaris (Loew) is a cosmopolitan polyphagous small fly with the ability of exploiting variety of ecological niches. Different life history stages act as detritivore, parasite, and parasitoid of wider spectrum of plant and animal matter under natural and laboratory conditions. Here, for the first time we present the opportunistic parasitism of M. scalaris on Otobius megnini, which act as a vector of Q fever and is capable of causing paralysis, toxic conditions, otoacariasis and otitis in humans and other animals. Tick samples from the ear canals of 14 thoroughbred horses were brought to the laboratory and several days later, larvae of M. scalaris were found feeding on immature stages of O. megnini. When the development was completed pupae were found attached to adult ticks and all nymphs were found dead. This context reveals the capability of M. scalaris surviving on O. megnini and the risk of their invading ear canals of horses.

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An island-wide collection of tick species infesting humans, domesticated and wild animals and questing ticks in domestic and peridomestic environments was carried out during 2009-2011. A total of 30,461 ticks were collected from 30 different hosts and free living stages from the ground. The collection consisted of 22 tick species from 30 different hosts recording 12 tick species from humans, 19 from domesticated animals and 21 from wild animals, with a total of 97 new host records. The most common tick species on humans were Dermacentor auratus and Amblyomma testudinairum, while Haemaphysalis intermedia, Rhipicephalus microplus and Rhipicephalus sanguineus were common in domesticated and wild animals sharing 20 host species. Among the questing ticks, immature D. auratus was the most abundant. Humans and domesticated animals were mostly infested by the nymphal stages while adult ticks were found on wild animals. High number of new host records could be due to domestic animals picking tick species from wildlife and vise versa at the human/animal interface. Habitat destruction due to forest fragmentation has lead to wild animals roaming in urban and semi-urban neighbourhoods increasing the interactions of wild animals with domesticated animals. Wild animals play a significant role as a reservoir of many tick borne infections which can easily be spread to domesticated animals and then to humans via tick infestations. Data in this paper are useful for those interested in tick infesting wild and domestic animals and humans in describing the zoonotic potential of tick borne infections.

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Megaselia scalaris (Loew) is a cosmopolitan polyphagous small fly with the ability of exploiting variety of ecological niches. Different life history stages act as detritivore, parasite, and parasitoid of wider spectrum of plant and animal matter under natural and laboratory conditions. Here, for the first time we present the opportunistic parasitism of M. scalaris on Otobius megnini, which act as a vector of Q fever and is capable of causing paralysis, toxic conditions, otoacariasis and otitis in humans and other animals. Tick samples from the ear canals of 14 thoroughbred horses were brought to the laboratory and several days later, larvae of M. scalaris were found feeding on immature stages of O. megnini. When the development was completed pupae were found attached to adult ticks and all nymphs were found dead. This context reveals the capability of M. scalaris surviving on O. megnini and the risk of their invading ear canals of horses.

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Many species of salmonids can discriminate kin from unrelated conspecifics using olfactory cues. In this study, we determined the role of the major histocompatibility complex (MHC) in kin discrimination by juvenile Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis). Genetic variation at the highly polymorphic exon coding for peptide-binding region of an MHC class II gene was studied using polymerase chain reaction and denaturing gradient gel electrophoresis. Experiments compared discrimination ability based on MHC haplotypes both within and among kin and non-kin groups. Juveniles chose kin sharing both alleles over kin sharing no alleles. Juveniles also preferred non-kin sharing both alleles to non-kin sharing no alleles. These data suggest that the MHC class II gene influence kin discrimination in juvenile Atlantic salmon and brook trout. The influence of additional genes was also apparent in trials where juveniles were able to recognize kin sharing no alleles over non-kin sharing no alleles. However, the inability of juveniles to discriminate between kin sharing no alleles and non-kin sharing either one or both alleles indicates that MHC is as potent as the rest of the genome in producing distinguishable odours.

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BACKGROUND AND OBJECTIVES: The involvement of private drug vendors in malaria treatment is particularly high in developing countries and understanding their practices and knowledge about antimalarials and malaria treatment will aid in devising strategies to increase the correct use of antimalarials and improve adherence to the government's malaria drug policy. Results of a study on the knowledge and practices of the private drug vendors conducted in seven districts in Sri Lanka, mostly in malarious areas are presented. METHODS: Data on awareness of government's malaria drug policy, practice of issuing antimalarials, knowledge about malaria and antimalarial drugs were collected from the drug vendors using pre-tested questionnaire in vernacular language. Data were statistically analysed using Stata 8.2. Chi-square test was carried out for individual explanatory variables and a logistic regression model was applied taking all response variables as binary outcome. RESULTS: Vendors' knowledge on antimalarials was poor with 58% of the vendors being unaware of the government malaria drug policy in the country. Also, the advice provided to customers buying antimalarials was limited. However, the majority of the private vendors emphasised that they were aware of the importance of case confirmation before treatment as stressed in the national policy. Although, the vendors did not have a high awareness of national drug policies they were only found selling chloroquine and primaquine as recommended by the Ministry of Health. INTERPRETATION AND CONCLUSION: In recent years Sri Lanka, as a whole, has experienced very little malaria. The reduction in demand for antimalarials due to low incidence levels may have influenced the knowledge and awareness on antimalarials and government drug policies. However, since low levels of malaria do not guarantee that epidemics will not occur, attempts to educate private drug vendors as a part of an organised control programmes are of major importance.

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