Community participation in malaria surveillance and treatment. III. An evaluation of modifications in the Volunteer Collaborator Network of Guatemala.

In most rural areas of Latin America, malaria surveillance and treatment is carried out by a network of unpaid village malaria workers, known as Volunteer Collaborators, who are trained and supervised by the National Malaria Service. To identify ways in which the performance of these volunteer workers could be improved and to test changes that would make the Volunteer Collaborator Networks (VCNs) a more attractive model for community participation in malaria case detection and treatment in other regions, we tested a series of modifications in the VCN of Guatemala. These modifications included improved methods for selecting, supervising, and evaluating the volunteer workers and for collecting blood smears and reporting results, and the use of volunteer workers, known as Volunteer Medicators, who administered presumptive antimalarial therapy without taking a blood smear. A cost-effectiveness analysis of the modified VCN was also carried out. Two years after the modifications were introduced, Volunteer Collaborators identified nearly twice as high a percentage (33% versus 17%) of patients with suspected malaria in their villages. Delays in examining blood smears were reduced from 23 days to 11 days and delays from blood smear examination to curative treatment were reduced from 21 days to 7 days. The Volunteer Medicators identified and treated only a slightly higher percentage of patients than the Volunteer Collaborators (36% versus 33%). However, the cost of maintaining a network of Volunteer Medicators ($0.61 per patient treated) was much lower than the traditional VCN ($2.45) or the modified VCN ($1.85). Thus, with a few, simple and relatively inexpensive modifications, the efficiency and cost-effectiveness of Volunteer Collaborators can be markedly improved. Additionally, the VCN can be modified to make it a more suitable model for community-based malaria control and surveillance networks in other malarious areas of the world, which differ in terms of their level of endemicity, the goals of the malaria program, or the available health care infrastructure.

Community participation in malaria surveillance and treatment. I. The Volunteer Collaborator Network of Guatemala.

The Volunteer Collaborator Networks (VCNs) of Latin America are one of the oldest and most successful examples of community participation in malaria control. They are made up of unpaid community volunteers, known as Volunteer Collaborators, who are selected by their neighbors and are trained and supervised by a member of the National Malaria Service (NMS). When a febrile patient visits the home of a Volunteer Collaborator, the volunteer worker takes a thick blood smear, completes a patient report form, and administers a presumptive treatment for malaria. The blood smear is examined in an NMS laboratory, and if malaria parasites are found, a radical or curative treatment is forwarded to the Volunteer Collaborator so that it can be administered to the patient. There is no charge for either the blood smear or the antimalarial medication. The VCN of Guatemala was established in 1958. Currently, more than 5,000 Volunteer Collaborator posts are operating throughout the malarious areas of the country. The volunteers range in age from 12 to 76 years old and 61% are men. Approximately 15% have no formal education, and only 27% have a sixth grade or higher education. The median length of service is 35 months (range three months to 26 years); 33% have worked for five or more years. Male Volunteer Collaborators had significantly lower turnover rates than females, as did married Volunteer Collaborators when compared with single volunteers. An inverse relationship was noted between the amount of education a Volunteer Collaborator had and his length of service. With modifications tailored to meet the objectives of a malaria control program and the local epidemiologic setting, the VCN can serve as an excellent model for community participation in malaria case detection and treatment in other regions of the world. In particular, in areas where the primary goal of the malaria program is to prevent mortality and morbidity through the provision of readily accessible, appropriate drug therapy, VCNs are an attractive alternative to self-medication and an effective adjunct to treatment of malaria at health posts which are often located at a considerable distance from the patient's village. Experience gained with this system can be valuable in developing approaches to community involvement in other efforts to improve the health of villagers in developing countries.

Community participation in malaria surveillance and treatment. II. Evaluation of the volunteer collaborator Network of Guatemala.

To evaluate the effectiveness of the Volunteer Collaborator Network (VCN) of Latin America as a community-based malaria case detection and treatment system, we conducted a study of the VCN of Guatemala. Volunteer Collaborators took 72.6% of all blood smears and identified 81.3% of all malaria cases reported by the Guatemalan National Malaria Service. The average volunteer treated 5.8 patients per month (range 0-32.8). In contrast, passive case detection (PCD) posts in government hospitals and health centers treated an average of 12.5 patients per month (range 0.5-91.4). The slide positivity rate of blood smears taken by Volunteer Collaborators was 16.2% compared with 9.7% for PCD posts in health centers and 10.3% for malaria workers during active case detection. The average delay between the date a blood smear was taken and examined ranged from 18.1 days on the Pacific coastal plain to 26.3 days in the less accessible northern region of the country. An additional 14.5 to 47.6 days elapsed before the radical treatments were initiated in these two regions. Seventy percent of the patients completed their radical treatments. In a survey conducted on the Pacific coastal plain of Guatemala, of 1,021 patients with chills and/or fever who believed they had malaria, 20.0% had visited a Volunteer Collaborator and 4.9% were treated at a government health center. Thus, the PCD network detected only 25% of all patients with symptoms suggestive of malaria. Most of the remaining patients treated themselves with antimalarial medications purchased in stores and pharmacies, but less than 15% of these patients used adequate courses of therapy. Furthermore, the rate of detection of symptomatic patients with malaria varied considerably from one community to another. Thus, data from the VCN are probably most useful when groups of communities or geographic areas are stratified for malaria control activities because at this level, variations between individual Volunteer Collaborator posts will be minimized. In spite of these problems, the VCN remains an excellent source of epidemiologic data for malaria control programs and the most practical means available for providing timely, appropriate antimalarial therapy to febrile patients in rural areas.

Use of illiterate volunteer workers for malaria case detection and treatment.

We evaluated the use of illiterate community volunteers for malaria case detection and treatment in Guatemala. Volunteer workers, known as Volunteer Medicators, were selected by members of their communities and were trained and supervised by National Malaria Service (NMS) staff. Their responsibilities included recording basic demographic data and administering a three-day course of chloroquine (25 mg kg-1) to all febrile patients who visited their homes. Patient information was recorded on a special form which consisted of stick-figure drawings. During a one-year evaluation period, no differences were noted between literate and illiterate Volunteer Medicators with respect to the length of time required for their training or supervision, the average number of patients they treated per month, the frequency of errors in recording data or administering medication, or their acceptance by the community residents.

Onchocerciasis in San Vicente Pacaya, Guatemala.

An epidemiological survey for onchocerciasis was carried out in the San Vicente Pacaya area of Guatemala. A total of 2,153 inhabitants were examined by a single skin snip, and 664 (30.8%) were positive for microfilariae. Slit lamp examination of the anterior chamber of the eye revealed microfilariae in 6.2%; the positive rate for microfilariae in the anterior chamber was proportional to the microfilarial density in the skin. The altitude-dependent character of onchocercal infection was shown in this mountainous area, suggesting that transmission occurs principally between 600 and 1,300 m. Of, 1,217 persons examined simultaneously by skin snip and by palpation for nodules, 587 were positive by one or both methods; 101 infections were detected by onchocercal nodules only and these were usually in children or persons living in areas of low endemicity. It was concluded that both the skin snip and a search for nodules are required for accurately determining the prevalence of onchocerciasis in Guatemala.