MALARIA CONTROL FROM THE INDIVIDUAL TO THE COMMUNITY

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1 MALARIA CONTROL FROM THE INDIVIDUAL TO THE COMMUNITY Calvin L. Wilson MD Clinical Professor of Family Medicine and Public Health University of Colorado Anschutz

2 OBJECTIVES 1. Understand the unique characteristics of malaria infection, and how this can affect control measures 2. Review the recommended prevention and treatment measures for an individual infected with malaria 3. Describe the community-based experience of malaria control in Rwanda 4. Discuss the traditional measures of malaria control, and compare with new innovations in control

3 BURDEN OF ILLNESS Found in almost all equatorial countries, as far south as South Africa, and as far north as southern Turkey Estimated over 200 million symptomatic episodes/year Over 100 million in Sub-Sahara Africa As many as 2 million deaths/year, 75% in children and infants.

4 DISTRIBUTION OF MALARIA

5 PATHOPHYSIOLOGY Parasitic infection caused by one of 4 species of Plasmodium vivax, malariae, ovale, falciparum Depends on Anopheles mosquito (2 species primarily) as vector, and mammals as intermediate host, primarily man Unique life cycle Sexual in mosquito (male and female gametocytes) Asexual and cyclic in mammal (man)

6 PATHOPHYSIOLOGY Within man, several parallel cycles in liver, development of hypnozoites (vivax & ovale) and merozoites within erythrocytes, formation of merozoites and rupture of infected RBC produces typical cycles of fever and prolonged infections

7 PATHOPHYSIOLOGY Hypnozoites thought to be a latent, quiescent infection - may lay dormant and asymptomatic for many years - documented as long as 30 years Some merozoites mature into gametocytes sexual forms that begin cycle in Anopholes gut when ingested Gametocytes ingested by mosquito and mature into infective sporozoites, which are injected into host with blood meal

8 LIFE CYCLE OF PLASMODIUM

9 PATHOPHYSIOLOGY Type of erythrocyte invaded depends on species of Plasmodium vivax & ovale - primarily only young RBC (reticulocytes) - limited in number malariae - mainly older, senescent RBC falciparum - any RBC - can lead to high parasitic burden

10 ANOPHELES MOSQUITO

11 ANOPHELES MOSQUITO Found world wide, mainly in tropical and semitropical area - dependent on humidity and temperature Sporogony (formation of infective sporozites) dependent on ambient temperature - between degrees Celsius Longevity of Anopheles dependent on relative humidity - longer in more humid environments

12 ANOPHELES MOSQUITO Only certain species capable of transmitting malaria infective types in each area - only female infective Generally found below 3500 ft altitude, but occasionally found as high as 7000 ft. Average life span about 30 days, flight pattern limited to about 300 meters Sexual phase of Plasmodium (range 8-16) days to complete in gut of Anopheles Mature mosquito infective only about days.

13 DIAGNOSIS OF MALARIA Diagnosed by clinical picture in endemic area Rapid slide test shows antibody formation in early stage Up to 90% sensitive, less so in endemic area Gold standard thick blood smear May require multiple smears for diagnosis in cases of low parasitemia 1 smear 40-50% sensitive 3-4 smears - 90% sensitive

14 INDIVIDUAL PREVENTION OF MALARIA Reduce biting of Anopheles long sleeves and slacks personal insect repellents avoid use of cosmetics and perfumes mosquito coils and space repellents screens on windows and doors use of insecticide treated mosquito nets for naps and sleep

15 INDIVIDUAL PREVENTION OF MALARIA Medication prophylaxis - areas of chloroquine sensitivity or R-1 resistance Chloroquine 300 mg base/week (500 mg chloroquine phosphate) must continue for 4 weeks after leaving area Areas of chloroquine resistance: Mefloquine 250 mg/week begin 1 week before prior and continue for 4 weeks after leaving area

16 INDIVIDUAL PREVENTION OF MALARIA Areas of chloroquine resistance (contd): Doxycycline 100 mg daily or tetracycline 500 mg qid begin 1-2 days prior and continue 4 weeks after leaving area) Malarone (atovaquone 250 mg/proguanil 100 mg) 1 tablet daily begin 1-2 days prior and continue 7 days after leaving area

17 COMMUNITY PREVENTION OF MALARIA Still mainstay of public health measures Most effective when a combination of measures used: 1. Reduce burden of Anopheles periodic spraying of interior of dwellings with residual insecticide draining of pools of stagnant water use of larvacidal fish in pools or bacteria

18 COMMUNITY PREVENTION OF MALARIA 2. Prevent contact with Anopheles with insecticide-treated bed nets (ITN) 3. Reduce burden of parasitemia in the population by early identification and treatment of all cases, regardless of severity 4. Use of artemether agents effective sterilization of blood of Plasmodium

19 MALARIA IN RWANDA % of all deaths in children <5 30% of admissions to district hospitals CHW allowed only to take thick smear for suspected malaria not to treat Patients had to go to district hospital for treatment and often only after smear positive (4-6 hours minimum)

20 CONTROL MEASURES INSTITUTED 2009 In addition to community education, ITN for ALL family members, and targeted mosquito spraying 80% all households with ITN All CHW trained in early diagnosis of malaria by symptoms, and given Rapid slide tests Artemether/Lumefantrine adult and pediatric Community members instructed to visit CHW at first sign of headache, malaise, and fever

21 RESULTS OF COMMUNITY CONTROL IN RWNADA Malaria incidence reduced by 66% across country up to 85% reduction some areas Rate of hospitalizations for malaria reduced by 7080% Incidence of death in children <5 reduced by 6570%.

22 MALARIA INCIDENCE BY APPROACH

23 BENEFITS OF COMMUNITY CONTROL OF MALARIA Community investment in control process Most of control process completed within the community, not in distant hospitals. Progressive decrease in reservoir of Plasmodium humans, which leads to: Logarithmic decrease in incidence of infection Less dependent on mosquito control

24 CHALLENGES OF COMMUNITY CONTROL OF MALARIA Human resource intensive especially training of adequate numbers of CHW (40,000 in Rwanda alone) Logistics intensive continual supplying all CHW with rapid slide tests and medication Expensive rapid slide tests about 5-10 times cost of thick smear analysis

25 CONCLUSIONS Malaria a multi-faceted problem with multiple potential points of control Recognition and management of malaria in the individual is well described and effective when begun promptly Individual control is feasible and effective, BUT Population/community control of malaria, especially directed toward reducing the human reservoir of Plasmodium, is even more effective.

Symptoms of Malaria. Young children, pregnant women, immunosuppressed and elderly travellers are particularly at risk of severe malaria.

Symptoms of Malaria. Young children, pregnant women, immunosuppressed and elderly travellers are particularly at risk of severe malaria. Preventing Malaria 1 Malaria is the world s most prevalent parasitic disease, accounting for an estimated 216 million cases with 655,000 deaths annually. Many people acquire malaria during travel to tropical