1. Parasites within us

Parasites within Us : Parasites within Us Dr Subroto Biswas

What are Parasites ? : What are Parasites ? = organisms that live in or on another species (the host) and have a negative effect on survival &/or reproduction of the host Differ from true predators in that they may not kill their host and if they do, it may take several generations of the parasite.

Which is more ?Parasites or Hosts : Which is more ?Parasites or Hosts Each animal is a host of many parasites; thus, there are far more parasitic organisms on earth than there are nonparasitic organisms. It has been estimated that more than 50% of all living plants and animals are parasitic at some stage during their life cycle.

Kinds : Kinds Interferons Bacteria Viruses Protozoans Nematodes Platyhelminthes Arthropods

Small but deadly… : Small but deadly…

Slide 6 : Sarcoptes scabei mite is about 0.4mm, just visible to the human eye Allergic itchy rash

Slide 7 : Dog tick life cycle - direct

Rickettsia cause Rickettsial fevers such as Rocky spotted mountain fever, typhus fever, scrub fever, Q-fever and trench fever. The vectors for these diseases are ticks and mites. : Rickettsia cause Rickettsial fevers such as Rocky spotted mountain fever, typhus fever, scrub fever, Q-fever and trench fever. The vectors for these diseases are ticks and mites.

LYME DISEASE : Tick carries the bacterium for Lyme disease Bulls eye rash is unique symptom of Lyme disease LYME DISEASE

Bacterial agents of Human diseases : Bacterial agents of Human diseases Tuberculosis ... Mycobacterium hominis Diptheria ... Corynebacterium diptheriae Cholera ... Vibrio cholerae Leprosy ... Mycobacterium leprae Tetanus ... Clostridium tetani Pneumonia ... Diplococcus pneumoniae Meningitis ... Neisseria meningitides Food poisoning... Clostridium botulinum Plague ... Pasteurella pestis

Causative agents of Human diseases : Influenza ... Hemophilus influenzae Typhoid ... Salmonella typhosa Whoophing cough ... Hemophilus pertusis Gonorrhoea ... Neisseria gonorrhoae Syphilis ... Troponema pallidum Boils ... Micrococcus pyogenes Relapsing fever ... Borellia recurrentis Causative agents of Human diseases

Slide 12 :

Slide 13 :

Recent estimates of the number of people infected with parasites in the world are: : Ascaris 1.3 billion Hookworms 1.3 billion Whipworms 1 billion Filarial worms 657 million Malaria 500 million Schistosomes 270 million Amebiasis 50 million Taeniad tapeworms 50 million Clonorchis 20 million Chagas’ Disease 15 million   These parasites cause untold suffering and death in the world today. Recent estimates of the number of people infected with parasites in the world are:

Helminths : Helminths Three groups of helminths relevant to medicine Nematodes (roundworms): GI tract or blood infections Cestodes (tapeworms) Trematodes (flukes) Three modes of human invasion: - Skin penetration - Contaminated food - Insect vector Under control in developed countries, millions of deaths / year in underdeveloped countries

Ascaris lumbricoides : Ascaris lumbricoides Roundworm is commonly called as giant intestinal round worm. Harbours small intestine of man More commonly in children Ascaris from human intestine (CDC)

Ascaris lumbricoides : Ascaris lumbricoides

Slide 18 : A circumpharyngeal nerve ring Males have single testis Fermale have two ovaries. A female can lay 27,000 000 eggs in her life time. The larva of Ascaris is called Rhabditiform larva.

Life cycle of Ascaris showsfour moults : Life cycle of Ascaris showsfour moults

Slide 20 : Ascaris causes ‘ascariasis’ With poor digestion, diarrohea & vomitting. Childern may suffer from growth retardation. Treatment includes oil of chenopodium with tetrachloroethylene. Drugs like Antepar, Piperazin citrates, Dewormis and others are useful.

Slide 21 : Ascaris causes ascariasis

Ancylostoma duodenale and Necator americanus : Ancylostoma duodenale and Necator americanus These hook worms are monogenetic endoparasites in the human intestine (jejunum or duodenum). Hook worm infection is widely distributed in all tropical and subtropical countries

Head of a hookworm with tooth like structures : Head of a hookworm with tooth like structures

Hook worms : Hook worms Where the humidity and temperature are favourable for the development of the larva in the soil. The larva infects man by boring through the skin of feet Life cycle completes in 7 weeks. Hook worm causes anaemia, intestinal lesions, pneumonia and retards growth in children.