Parasitc zoonoses: Different modes of Human infection are: Foodborne Vectorborne Inanimate objects born viz. soil, plants (Saprozoonoses) Based on etiology: • Helminthic i. Trematodal • Protozoal ii. Cestodal • Arthropodal iii. Nematodal Contd.. Snail borne diseases Contd.. Trematode Final host Intermediate host Transmission to humans Fasciolopsiasis: Man, dog and buffalo; Snail Ingestion of Fasciolopsis buski Pig (reservoir) metacercaria on water chestnut Schistosomiasis: Man and other Snail Skin penetration S. hematobium, mammals by cercaria S. mansoni, S. Japonicum Clonorchiasis: Man, dog, cat, pig, rat 1st snail Ingestion of cyst Clonorchis sinensis 2nd freshwater in fish (Chinese liver fluke) fishes esp. cyprinid Opisthorchiasis: Man and fish eating 1st snail Ingestion of cyst Opisthorchis felineus mammals; Dog and 2nd cyprinid fish in fish O. viverrini cat-(reservoir) Paragonimiasis: Man, dog, cat and 1st snail Ingestion of cyst Paragonimus other mammals 2nd fresh water in crab meat westermanni crabs and fishes Fasciolopsiasis: •Fasciolopsis buski •Intestinal-ulcerous disease in humans •Humans and pigs are final hosts; pigs are reservoirs. Infective stage (metcercaria) via ingestion of contaminated water chest nuts and walnuts which are eaten raw. Contd.. Occurrence: Areas of endemicity are large parts of the People’s Republic of China and Taiwan, India, Bangladesh, Indonesia, Thailand, and Vietnam. Disease occurs focally and is most prevalent in school-age children. The prevalence of infection in children ranges: 60% in India 57% in China 50% in Bangladesh 25% in Taiwan, and 10% in Thailand [Nithiuthai et al. 2004] Schistosomiasis (Bilharziosis) Common in tropical and subtropical areas Schistosome Type of infection Occurrence Reservoir Hosts species caused (highly (zoonotic) prevalent) S. hematobium Schistosomiasis of North America, Not important, but urinary tract Africa monkey, pig and rodents may play role S. mansoni Intestinal East, Central Monkeys and rodents Schistosomiasis and West Africa, and Egypt S. japonicum Asian intestinal Southeast and Domestic ruminants, schistosomiasis East Asia dogs, and rodents Contd.. In India, Schistosoma hematobium is endemic in village Gimvi, Ratnagiri district of Maharashtara Percutaneous penetration of infective stage (cercaria) Skin lesions Hepatomegaly Lymphadenopathy Encephalopathy Many species are known to causing “Swimmer’s itch”, but no authentic information on prevalence in humans. Schistosome cercaria Swimmer.’s Itch /Cercarial dermatitis Chlonorchiasis and Opisthorchiasis •Both parasitize in bile duct system Chlonorchis sinensis •Occurs in all Asian countries. •In Korea, Vietnam, Taiwan, and the People’s Republic of China, prevalence rates in humans are up to 50%. •Besides humans, cats, dogs, pigs and various carnivores are serving as final host. (Krauss et al. 2003) Opisthorchis species Endemic areas O. felineus Eastern and Southern Europe O. viverrini South East Asia and East Asia Contd.. Human infection occur by ingestion of uncooked or undercooked freshwater fish, esp. cyprinid fishes e.g. carp. Paragonimiasis (Pulmonary distomiasis) • Lung flukes of the genus Paragonimus • Paragonimus westermani is prevalent predominantly in Central, Southeast and East Asia. High prevalence in humans is expected in north-eastern states in India as crab and dog meat are delicacies there [Borthakur et al. 2007]. Zoonotic hookworm infections (Ancylostomiasis) Ancylostoma Disease in humans Final host species Ancylostoma Eosinophilic enteritis Dogs caninum (occasionally) A. braziliense Cutaneous Larva Dogs Migrans(CLM) A. ceylanicum Anaemia and intestinal Dogs, jangle cats, infection civet Ancylostoma caninum is the most common and is worldwide. • In Madhya Pradesh, prevalence among stray dogs reported is 89%. [Sahasrabudhe et al. 1969] and in tea growing communities in Assam , it is 72%. [Traub et al. 2004] Contd.. •Up to 60% of dogs in tea growing communities of Assam harboured A. braziliense, with 37% of dogs having mixed infections with A. braziliense and A.caninum. [Traub et al. 2004] Humans are accidental hosts and High incidence of get infection by percutaneous CLM in the area penetration of larva. and majority of individuals (67%) admitted to walking barefoot while outdoors [Traub et al. 2004]. Contd.. •There are no reports of A. ceylanicum infections in dogs despite the isolation of the hookworm in 16 out of 173 humans from the Hoogly region. [Chowdhury et al. 1972] CLM (Creeping Eruption) Disease is acute and self-limiting. Etiological agent Favourable climate Ancylostoma braziliense Tropical and subtropical areas Uncinaria stenocephala Cold and moderate climate Contd.. Cutaneous larva migrans (CLM) Visceral Larva Migrans A syndrome caused by the invasion of inner organs (liver, lungs, brain) or the eye by nematode larvae of the genus Toxocara canis, and to a lesser extent, T.cati (T. mystax). Parasite Definitive host Paratenic host Toxocara canis Dog, fox; less Essentially every prevalent in other species of mammals, canids, e.g. coyote, and birds wolf, jackal Toxocara cati Cats and other Rodents and birds felidae Baylisascaris Racoons Rodents and birds procyonis Contd.. •Human infections occur worldwide. •Antibodies to T. canis are found worldwide in 2 to 14% of the human population, with higher prevalence in children than in adults (Krauss et al, 2003). •Humans are accidental hosts and get infection by accidental ingestion of embryonated eggs. Contd.. In Dogs Parasitic surveys found T. canis to be most common parasite of stray dogs in Miraj (prevalence 55.8%) and Calcutta (prevalence 82%). [Joshi et al. 1977, Mapplestone.1940] By contrast, the prevalence of T.canis in adult stray dogs in Madhya Pradesh was found to be 2.7% and in tea growing communities in Assam , it was 11%. [Malla et al. (2002); Traub et al. 2002] In another study, 46% of public parks and 32% of school grounds in Andhra Pradesh were contaminated with Toxocara ova. [Kumar and Hafeez. 1998] Contd.. In humans In a random rural survey in Haryana, 6.4% prevalence rate was found. [Malla et al. (2002)] Stunning, 23.3% prevalence has been found in Chandigarh in ocular cases and rate was 20.5% in New Delhi. [Mirdha and Khokar 2002] 4 types of clinical syndromes associated with T. canis are: 1. VLM 2. OLM 3. NEUROLOGICAL 4. COVERT TOXOCARIASIS Contd.. Ocular Larva Migrans (OLM) Trichinellosis (Trichinosis) Nematodes of the genus Trichinella. Caused by consumption of poorly cooked meat of a number of species, especially of pig. Autopsy surveys indicate that about 2% of the population is infected globally (Uni. Of South Carolina online). More frequent in temperate than tropical areas. Incidence higher in winter season. Contd.. In India, most of human cases go undetected. [Dupouy-Camet, 2000] In past, many human cases had been reported by different workers. [Alipuria et al. 1996; Mohan et al. 2002] 15.79% prevalence rate in panthers and tigers of the Ranthambore National Park had been reported. [Singh. 2000] In number of species like cats, bandicoots and country pigs, Trichinella infection had been described. [Uppal. 2000] Zoonotic filariasis Lymphatic filariasis Wuchereria bencrofti Filariasis (non-zoonotic) Dirofilariasis Brugia malayi (both zoonotic and non-zoonotic) Zoonotic in country In India Non-zoonotic Dirofilaria repens (Natural host is dog) Subcutaneous lesions only Transmission is by bite of various mosquitoes. Contd.. In Kerala, a high prevalence of filarial worms in the subcutaneous tissues and subconjunctival space of human beings has been found. From Kerala, 12 worm specimens of Dirofilaria repens (2002 to 2004) have been identified from human cases. During the same period, in 7% dogs’ blood smears microfilariae have been detected. [Sabu et al. 2005] Taeniasis and Cysticercosis Taenia species Adult tapeworm Metacestode (final host) (intermediate host) Taenia saginata Humans Cattle, reindeer; wild saginata ruminants T. solium Humans Domestic and wild pigs; humans; also, dogs T. saginata asiatica Humans Domestic and wild pigs; also, cattle, goats, monkeys Taeniasis (non-fatal) Cysticercosis (often neurocysticecosis and is lethal) Contd.. Cysticercosis: Neuro-cysticercosis (most common) Ocular cysticercosis Muscular and S/C connective tissue (10% in India) (Uni. of South Carolina online) Neuro-cysticercosis is responsible for most of the morbidity/mortality observed in cases of human cysticercosis. [Pedro N. Acha and Boris Szyfres. 2003] Contd.. At HIMS hospital, Dehradun, 32.0% patients clinically manifesting neurological signs (33/103) were positive for T. solium IgG antibodies in their sera. Among these patients children (11-20 years age group) were most affected (39.4%). [Kumar et al. 2006] In Pondichery, 14/216 (6.48 %) male blood donors are found to be positive for either anti-Cysticercus antibodies or antigens by ELISA. [Kaliaperumal et al. 2005] A number of ocular cysticercosis cases have been reported in the South India. [Kaliaperumal et al. (2005)] In a study at IVRI, 3% prevalence of neurocysticercosis has been in the 200 slaughtered pigs’ brain samples in the Bareilly region. [Prakash et al. 2007] Contd.. Diphyllobothriasis Diphylobothrium latum, the largest cestode of humans. Predominantly in temperate and sub arctic areas of Northern hemisphere. Infection by ingestion of uncooked or partially cooked contaminated fish Contd.. Besides humans, major hosts are cats, dogs and pigs but all other fish eating mammals may become infected. Megaloblastic anemia and neurological signs are