Summary

In this study session, you have learned that:

• Schistosomiasis is caused by parasitic flatworms transmitted from freshwater snails to humans. It is common in communities living near rivers, lakes and streams, where infected people shed Schistosoma eggs when they urinate or defaecate into the water.
• Schistosoma mansoni affects blood vessels in the intestines and causes abdominal pain, bloody diarrhoea and anaemia. Schistosoma haematobium affects blood vessels in the bladder and causes pain during urination and bloody urine.
• Leishmaniasis is caused by protozoan parasites transmitted to humans through the bite of sandflies, which breed in warm, humid places such as rubbish collections and rodent burrows.
• Leishmania donovani causes the life-threatening condition called visceral leishmaniasis (or kalaazar), manifested by fever, weight loss and swelling of the liver and spleen. Three other Leishmania species cause cutaneous leishmaniasis, which manifests as ulcers in exposed areas of skin.
• Onchocerciasis is caused by a nematode worm (Onchocerca volvulus) transmitted in the bite of blackflies, which breed near fast-flowing rivers with good vegetation. The microscopic microfilaria cause skin nodules and can migrate to the eye, causing blindness.
• Lymphatic filariasis (or elephantiasis) is caused by a nematode worm (Wuchereria bancrofti) transmitted to humans in the bite of female mosquitoes. The worms block the lymphatic system, causing swelling of the limbs and sometimes the genitals, resulting in severe pain, disability and bacterial infection of thickened skin folds.
• Integrated vector control measures such as indoor residual spraying, use of insecticide treated bed nets (ITNs), chemical treatment of water, use of personal protective clothing and environmental management to destroy vector breeding sites are key interventions to prevent these vector-borne diseases.
• Mass drug administration of the entire at-risk population at regular intervals for several years is the recommended strategy to prevent onchocerciasis and lymphatic filariasis in endemic communities.
• Educating the community on the modes of transmission of vector-borne diseases, effective prevention strategies, and early diagnosis and referral of patients are important activities for primary healthcare professionals in affected areas.