Field evaluation of malaria rapid diagnostic tests for the diagnosis of P. falciparum and non-P. falciparum infections.

The objective of this study was to evaluate various malaria rapid diagnostic tests as a tool in the detection of P. falciparum and non-P. falciparum infections in field conditions. Four field surveys were conducted in malaria-endemic areas of Palawan and Davao del Norte, Philippines to validate the various rapid diagnostic tests, namely Diamed OptiMAL 48 (DiaMed AG, Switzerland), ParaHIT f (Span Diagnostics, India), Orchid OptiMAL, and Paracheck Pf (both from Orchid Biomedical Systems, India). The results of the various rapid diagnostic tests were compared to those of microscopy. Sensitivity, specificity and detection rates according to the level of parasitemia were used as parameters to describe the performance of the various rapid diagnostic tests in the field. Practical and operational assessments were also done. The results of the study show that the sensitivity and detection rates were generally lower than previously reported, with sensitivities ranging from 4.8% to 20.6%, except for Diamed OptiMAL 48, which had sensitivities of 78.8% to 96.8%, and detection rates of 50.0% to 96.8%. The rest had detection rates ranging from 0.0% to 50.0%. All the specificities ranged from 18.2% to 100.0%. Improper conditions at the time of manufacturing, storage, transport, and utilization may affect the validity of the results. Rapid diagnostic tests for malaria provide practical means of detecting malarial infections, especially in endemic areas. However, issues regarding variability in performance must to be addressed before they can be used as mainstream diagnostic tools.

Intestinal heterophyidiasis: an emerging food-borne parasitic zoonosis in southern Philippines.

Heterophyidiasis is an infection of the small bowel by minute intestinal flukes of the genus Heterophyes or related members of the family Heterophyidae. To provide a better understanding of this rarely reported condition, this study attempted to determine the infection rate, intensity of infection as well as the clinical spectrum of heterophyid infection. A stool survey was conducted in barangay San Isidro, Monkayo, Compostela Valley. Thirty-six percent of patients with history of bowel disturbance (abdominal discomfort/pain and/or diarrhea) in the past 4 weeks were found to have heterophyidiasis. All age groups were infected, with the youngest patient being 1 year 7 months of age, while the oldest patient was 73 years of age. Prevalence was highest in the 15 to 30 years old group at 55.3%. The most common clinical manifestations of heterophyidiasis were signs and symptoms of acid peptic or peptic ulcer disease. Early diagnosis and treatment are important to ensure prompt resolution of heterophyid infection, hence, decreased morbidity and decreased chances for complications like heart or brain involvement. Proficiency of laboratory staff should be enhanced to ensure accurate diagnosis which will then make appropriate treatment possible.

Compostela Valley: a new endemic focus for Capillariasis philippinensis.

A 20 year old female from Compostela Valley Province in the Philippines, presenting with chronic diarrhea, borborygmi, bipedal edema, anorexia and weight loss was seen at Davao Regional Hospital. Her stool specimen, suspected by a local medical technologist to have Capillaria philippinensis ova, was forwarded to the Diagnostic Parasitology Laboratory of the College of Public Health, University of the Philippines Manila. It was examined and found to contain Capillaria philippinensis adults, larvae and eggs. Twelve deaths among people coming from the same barangay, affected by a similar illness with no definite diagnosis except "gastroenteritis" were also reported. These prompted health officials to send a team that would investigate the etiology of the disease outbreak labeled as a "Mystery Disease". Seventy-two stool samples from symptomatic patients were examined. Fifty-three (73.6%) individuals were proven to harbor at least one parasite with 16 (22.2%) individuals positive for Capillaria philippinensis infection. Ocular inspection, interviews and focus group discussions revealed that the people's eating habits are not much different from the habits of those from the Ilocos provinces where capillariasis was initially described. In both areas, people are fond of eating kinilaw or raw fish. They also eat raw shrimps, crabs and snails. Furthermore, the people defecate in the field or in the same body of water where they get the fishes, shrimps, crabs and snails that they eat, thus completing the life cycle of Capillaria philippinensis. Fish-eating birds were likely to have spread this parasite to the area. This is the first report of a capillariasis outbreak in Compostela Valley Province, and this should alert health authorities to consider embarking on serious efforts for developing proficiency of laboratory and clinical diagnosis especially in government health facilities where the poor and marginalized sectors of society are likely to consult.

Pulmonary paragonimiasis and tuberculosis in Sorsogon, Philippines.

The clinical epidemiology of pulmonary paragonimiasis and tuberculosis was investigated in a known endemic municipality of Sorsogon, Philippines. Records of diagnosed tuberculosis patients on treatment and follow up at the local Rural Health Unit over a two year period from 1993 to 1994 were reviewed to provide an overview of pulmonary tuberculosis in the area, specifically to describe the population at risk, the basis for diagnosis and the proportion of case notification who were sputum negative. Patients from the same group of individuals as well as undiagnosed tuberculosis patients with productive cough, fever with chest and/or back pain, or hemoptysis were examined to look into clinical manifestations, duration of symptoms, history of crab-eating and sputum examination results for acid-fast bacilli and Paragonimus. There was difficulty in determining the number of non-responders as the records did not have any provision for the recording of such. Annual tuberculosis case notification rates for the two years (374 and 401 per 100,000 population) were higher than the national figure in 1991 (325 per 100,000 population) indicating that tuberculosis is still a major health problem in the area and tuberculosis control efforts may have to be more aggressive to better contain the disease. Twenty-six out of 160 individuals surveyed were sputum smear positive for Paragonimus. Paragonimiasis rates were not significantly different in the two groups (15.6% vs 16.9%, respectively) indicating that there is a need for routine sputum examination for Paragonimus which is not available at present. Only six patients surveyed were sputum smear positive for acid-fast bacilli. A high index of suspicion is necessary to diagnose paragonimiasis and to be able to differentiate it from tuberculosis. The diagnosis may be suggested by a patient's place of origin being a known endemic area, a long period of chronic cough and the habit of eating raw or insufficiently cooked crabs or crayfish. Laboratories in endemic areas should have the capacity to differentiate between the two infections by being able to provide the routine laboratory procedures necessary for definitive diagnosis and treatment.

Problems with filariasis control in the Philippines.

Problems with filariasis control in this country of more than seven thousand islands are presented and discussed according to the political, economic, and socio-behavioral aspects. Discussed are issues relating not only to the recipients of the health services and control programs but also to the people in the control program and disease control managers. Marinduque, a recently described endemic focus of lymphatic filariasis, is used to illustrate the many problems affecting the control efforts in the Philippines. The true impact of the problem has not been described lately, hence the need for epidemiologic, social, and economic impact studies.