Question

Project Paper:

Subject: Descriptive Epidemiology of a Selected Health Problem (10 pages, single spaced)

Select one health problem from those listed below to explore in detail by using a descriptive epidemiologic approach.

Acquired immune deficiency syndrome (AIDS

Anthrax

Escherichia coli (EHEC) Infection

Hepatitis A

Hepatitis B

Lyme disease

Malaria

Rabies

Severe acute respiratory syndrome (SARS)

Smallpox

Syphilis

Yellow fever

Any other

How you should organize the paper:

1. Define the problem (nature, extent, significance, etc)
2. Describe the agent.
3. Describe the condition briefly.
4. Examine the above sources for data on morbidity and mortality for the selected problem.
5. Summarize these data on the distribution of the selected health problem according to the following factors, using tables, graphs, or other illustrations whenever possible:

1. Host characteristics
   1. Age
   2. Sex
   3. Nativity
   4. Marital status
   5. Ethnic group
2. Environmental attributes
   1. Geographic areas
   2. Social and economic factors
      1. Income
      2. Housing
   3. Occupation
   4. Education
3. Temporal variation
   1. Secular
   2. Cyclic
   3. Seasonal
   4. Epidemic
4. Any additional characteristic that contributes to an epidemiologic description of the disease

6. Summarize any current hypotheses that have been proposed to explain the observed distribution.
7. List the principal gaps in knowledge about the distribution of the health problem.
8. Suggest areas for further epidemiologic research.
9. Critically appraise the data as a whole, consult primary sources and important original papers.

Answer 1

MALARIA

Malaria is a parasitic infectious disease caused by Plasmodium species. There are 5 Plasmodium species out of which P.falciparum and P.vivax are more common and crucial.

Malaria is transmitted by bites of infected female anophelus mosquitoes. ( Transmission can also happen transplacentally, by blood transfusion or by needle sharing).

Malaria is a life threatening disease which is present worldwide. It affects around 500-600 million people /year and the death rate is about 1-3 million/year. Children under 5 years are the most vulnerable group affected by malaria.

Most of the malaria cases and deaths happen in sub-Saharan Africa. However, Asia, central and south america also at risk.

There are 5 species of malarial parasite , Plasmodium - P. falciparum, P. vivax, P. ovale, P. malariae, P.knowlesi. Plasmodium has got an interesting life cycle in man and in mosquiotoes.

When an infected mosquito bites a human , it injects sporozoitrs of parasite into the bloodstram . They gets into the liver cells and develops into merozoites. Matured liver schizont ruptures and merozoites are released to blood stream and they gets into RBCs. Inside the RBC they develops into male and female gametes. When blood is again sucked by mosquitoe , these gametes gets into mosquitoe gut and fertilisation happens there. sporozoits formed as as a result of fertilisation are stored inside the salivary gland of mosquitoes. When they bites, these sporozoites gets into blood stream and the cycle continues.

Malaria is a febrile illness . Symptoms usually develops after10 - 15 days of mosuito bite. Common symptoms are fever and chills ,profuse sweating, head ache, nausea and vomiting, diarrhoea, abdominal pain, blood in stools etc. Malaria shows relapsing type of fever in which temperature returns to normal for dys before rising again.

Prevalance of malaria is very high as shown in graph above. by WHO.

Epidemiology of malaria depend upon

A. Hosts like infants, children below 5 years, pregnant women, patients with HIV infection , migrants and travellers. Children below 5 years accounted for 67% of all malaria deaths worldwide.  

B. Malaria is prevalant among low socio economic status people. Housing facilities like slum areas , low education status are leading to occurance malaria.

Geographically malaria is prevalent in sub Saharan africa, asia , america etc. In 2018, the following countries reported more than half of the total malaria cases worldwide - Nigeria, Congo, Uganda, Mozambique and niger.

C. Malaria is common during rainy seasons. Temperature and humidity affectsbthe life cycle of mosquitoes ao that it affects malaria epidemic.