ticks and tick-borne diseases
Ticks are ectoparasites of terrestrial vertebrates with medical and veterinary importance. Up to now there are 896 described species of ticks of which many are distributed in warm and moist climates. They have remarkable longevity and ability to withstand starvation for many years (some up to 18 years) without a blood meal. Ticks are second only to the mosquitoes as vectors of many infectious diseases. So far, 808 tick-pathogen relationships which are important to animals and humans have been identified. Tick-borne pathogens and ticks have co-evolved with various wild reservoirs and often live in a state of equilibrium. However, when the domesticated animals come in to contact with wild animals for example due to the overlap of their grazing pastures, ticks and tick-borne pathogens are introduced to humans through livestock and also through pet animals.
Eco-epidemiology of Spotted Fever Group Rickettsioses (SFGR)
SFGR is caused by Rickettsia bacteria with humans being incidental hosts. Currently the incidence of tick-borne rickettsial infections is increasing worldwide. Since 1990’s much attention is paid for laboratory and field studies but rickettsial infections continue to rise with many previously unknown SFGR with varied pathogenecity and epidemiological attributes presenting new challenges to the medical and public health communities. Among the major contributing factors for this increase, ecological factors particularly those driven by climate change, human population increases and behavioral changes (recreation, nature tourism, etc) have been listed. Non-specific signs and symptoms and the absence of widely available sensitive and specific diagnostic test make them difficult to diagnose. Little is known about the rickettsial disease in Sri Lanka. In 2003, the first record of rickettsia from the central hills of Sri Lanka reported SFGR, scrub typhus (caused by Orientia tsutsugamushi) and murine typhus (caused by Rickettsia typhi). We study the type of pathogens, vertebrate reservoir community composition maintaining the natural cycle of SFGR and the ticks and other possible vector species on circulation and maintenance of pathogens of SFGR in the Central Province of Sri Lanka.
Otoacariasis of Humans and Domesticated Animals
The presence of ticks in the external auditory canal is known as otoacariasis which is relatively a common occurrence in domesticated and wild animals but rarely reported in the medical literature. We study the types of tick species associated with otoacariasis in humans and domesticated animals, their life cycles, the seasonality and socio-ecological risk factors.
Canine Tick-Borne Infections
Tick-borne diseases in dogs represent a substantial diagnostic challenge for veterinarians in that clinical signs are often diffuse and overlapping. In addition, co-infections with two or more pathogens enhance this problem further. Molecular methods are useful to disentangle co-infections and to accurately describe prevalence and geographical distribution of tick-borne diseases. There is a relative paucity of studies into canine Babesia, Ehrlichia, Anaplasma, Hepatozoon and haemotropic Mycoplasma infections in Sri Lanka.
GASTROINTESTINAL PARASITES
Effect of gastrointestinal (GI) parasites of humans on microbiota and respiratory diseases
The effects that GI nematode infections exert on the commensal flora of the vertebrate hosts have long been neglected; however, recent studies have contributed preliminary information to this little known field of research, mainly driven by the need to better understand the factors that determine the immune-modulatory properties of selected species of parasitic nematodes. While no notable shifts in the make-up of the gut commensal flora were observed over the course of these studies, increases in microbial species richness and diversity were detected following experimental infections.However, these studies, conducted under controlled experimental settings and with a known number of infective larvae, are unlikely to represent ‘real-world’ infections (caused by the simultaneous presence of multiple parasite species with varying infection burdens).
Diversity, prevalence and, epidemiology of GI parasites in wild, captive and domesticated animals and their zoonotic potential
We apply the One Health concept bringing together human and animal health in a holistic approach to diagnose the GI infectious agents and identify zoonotic potential at the human-animal interface. Over the coming years, global health practitioners anticipate an increased incidence of enteric diseases, particularly zoonotic parasites, due to several One Health-related drivers. These factors include dietary changes and food trends, population growth and habitat expansion, climate change, increasing global food markets and trade, intensive farming and agriculture practices, human and animal movement, and longer life spans with resulting chronic illness. A large scale epidemiological investigation involving a considerably larger sample size in wider host range would provide better insights into the prevalence and infection intensity of GI parasites especially the soill transmiitedd nematodes such as Trichuris, Ascaris and hookworms in Sri Lanka. Subsequent molecular characterization of the Trichuris spp., Ascaris spp. and Ancylostoma spp. in different hosts would provide the first molecular evidence of the STN species in Sri Lanka.he One Health concept provides an integrated framework for observing and improving health issues involving human, animal, and environmental factors, and has been applied in particular to zoonotic disease problems.