Infectious diseases

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Symptoms: severe diarrhoea up to 20 liters a day of “rice water stool”, vomiting, muscle cramps caused by loss fluid and electrolytes.

Pathogenesis: Vibrio adheres to the small intestinal lining, multiply and produce the enterotoxin choleragen which causes the accumulation of cAMP. An increased secretion of water and electrolyte from the cells results

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Cholera

4. Epidemiology: Feacally contaminated water, crabs and vegetables fertilized with human faeces. Has been eradicated most developed countries but a new strain discovered in 1992 is threatening another pandemic.

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Cholera

5. Incubation period: 12-48 hours

6. Lab diagnosis: Microscopy, culture of sample from faeces or vomit.

7. Prevention: Purification of water, washing of hands.

8. Treatment: administration of solution of glucose and electrolyte orally or intravenously; tetracycline antibiotic orally

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Malaria

Causative Agent: Plasmodium (4 species)

Symptoms (Clinical features): fever, chills, anaemia, headache, nausea, shivering, convulsions (esp. in under 5 yr olds) enlarged spleen.

Pathogenesis: site of action of pathogen include: liver, RBC, brain. The vector, female Anopheles mosquito, transfer pathogen during feeding.

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malaria

4. Epidemiology: Endemic in 91 tropical and subtropical countries. Invade the liver 1st and move to reproduce in RBCs resulting in their rupture and the associated chills.

5. Incubation Period: 1 – 2 weeks.

6. Lab diagnosis: Microscopy.

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An Infected RBC

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Malaria - Prevention

Reduce the number of mosquitoes; destruction of larvae and adult mosquitoes by biological and chemical control methods

Avoid being bitten; protective clothing and creams, treated bed nets

Use of drugs to prevent infection; chemoprophylaxis

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Malaria -Treatment

Combination therapy: Artesunate Amodiaquine

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Tuberculosis

Pathogen: M. tuberculosis (pulmonary TB); M. bovis(GI TB)

Transmission: airborne droplets (NB MTB is dessication resistant and survives in dried sputum); unpasteurized milk.

Clinical features: prolonged coughing sometimes with bloody sputum, shortness of breath, fever, sweating , weight loss