Annals of Tropical Medicine & Parasitology
ISSN: 0003-4983 (Print) 1364-8594 (Online) Journal homepage: http://www.tandfonline.com/loi/ypgh19
Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines John H. Cross, Clarence Wheeling, Tirso Banzon, Virginia Basaca-Sevilla & Josue Sevilla To cite this article: John H. Cross, Clarence Wheeling, Tirso Banzon, Virginia BasacaSevilla & Josue Sevilla (1977) Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines, Annals of Tropical Medicine & Parasitology, 71:4, 435-441, DOI: 10.1080/00034983.1977.11687209 To link to this article: http://dx.doi.org/10.1080/00034983.1977.11687209
Published online: 15 Mar 2016.
Submit your article to this journal
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ypgh19 Download by: [Cornell University Library]
Date: 29 June 2017, At: 22:16
Annals of Tropical Medicine and Parasitology, Vol. 71, No. 4 (1977)
Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines* Bv JOHN H. CROSS, CLARENCE WHEELING
U.S. Naval Medical Research Unit No. 2, Taipei, Taiwan TIRSO BANZON, VIRGINIA BASACA-SEVILLA
AND
JOSUE SEVILLA
The Bureau of Research and Laboratories, Philippine Health Department, Manila, Republic of Philippines Rectived 9 August 1976 Reports of epidemics of amoebiasis are not uncommon to public health authorities throughout the world and when investigated the reported increase in epidemic incidence often reveals misidentification of the parasite, Entamoeba histolytica, artefacts in stool specimens, or inaccurate diagnoses by inexperienced physicians. An increased reporting of cases may be authentic, however, and due to quite accurate diagnoses by technicians and physicians. We consider the present report an example of the latter. A private hospital located on the island of Cebu (Fig. I), Central Philippines, became concerned by the number of patients diagnosed as having intestinal amoebiasis. The Bureau of Research and Laboratories of the Philippine Health Department was informed and an investigation was carried out in July 1973 by a team of physicians, parasitologists and technicians from the Philippine Health Department and the U .S. Naval Medical Research Unit {NAMRU) No. 2. The investigation consisted of stool and serological examinations and a questionnaire survey. MATERIALS AND METHODS
Study Area The reporting hospital, operated by a large copper mining corporation, was staffed by well-trained physicians and laboratory personnel and provided care for approximately 7200 company employees and their families. The population of the surrounding barrio (village) was approximately 35 000 and the company was the major source of income for the entire area. Most of the labourers who worked for the company lived in the barrio, while the administrative and engineering staff were provided housing on the company compound. The water supply for part of the barrio came from an underground spring piped to outlets along the streets. Certain barrio subdivisions obtained chlorinated water piped from the company-owned deep wells while other water was from open or closed wells or small streams. Sanitation was excellent on the company compound, but in the barrio, toilet facilities consisted mostly of water seal toilets, outside privies or nearby fields.
* This study was supported through funds from the Bureau of Research and Laboratories, Philippine Health Department and the Naval Medical Research and Development Command, Navy Department, for Work Unit MR041.09.01-0146. The opinions and assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the Philippine Health Department, the U.S. Navy Department or the Naval Service at large. Reprint requests to Publication Office, NAMRU-2, Box 14, APO San Francisco 96263, or 7-1 Kung Yuan Rd., Taipei, Taiwan, ROC.
436
AMOEBIASIS ETC. ON CEBU, PHILIPPINES
Fig. 1. Map of the Philippine Islands showing Cebu and the area near Toledo where the survey was conducted.
Company houses were well constructed of wood or cement blocks, while barrio houses were of wood, cement blocks, bamboo or nipa. The terrain was rocky, with an elevation of approximately 1100 feet (335 m). The climate in this part of Cebu is relatively dry from November to April but wet for the rest of the year. The survey was carried out by asking company employees and their families to report to the hospital. All were volunteers; no attempt was made at random selection.
Serological Diagnosis Venous blood was obtained by vacutainer and sera separated by centrifugation and placed on dry ice. Sera were tested for E. histolytica antibodies by the microtitre adaptation of the
CROSS eta/.
437
indirect haemagglutination test (IHA) (Milgram et al., 1966) using antigens prepared from axenic cultures of the HK9 strain of the parasite (Thompson et al., 1968). Sera were inactivated at 56°C prior to testing and known positive and negative controls were used with each test series. Two-fold serial dilutions from I :4 to 1:8192 were tested and reciprocal antibody titres equal to or greater than I :128 were considered positive.
Parasitological Diagnosis Stool cartons were distributed to all participants and portions of the returned faecal specimens were placed individually in screw-capped vials containing 10% formalin and in vials containing polyvinyl alcohol (PVA). Consistency of the stool specimens and the presence of blood and mucus were recorded. Formalinized stool specimens were examined microscopically by direct and formalin-ether concentration (DFEC) methods and PVA specimens were smeared onto microscope slides, dried, stained with trichrome stain (PVAT) and examined microscopically. Each participant or a reliable third party was interviewed by a nurse or physician and a questionnaire completed relating to occupation, eating habits, toilet facilities water supply, animal contacts, history of diarrhoea and passage of mucus and blood in the stools. RESULTS
Serological Findings Sera were obtained from 1029 persons, 550 males and 479 females, aged 2-79 years; 43 or approximately 4% of the total tested had E. histolytica antibodies at titre ~ I :128. Overall, more male (28, 5%) than female (15, 3%) sera had positive antibody titres, but the distribution of seropositives by age group was variable. In those aged two to nine years 2% had antibodies, but titres were not detected in sera from those aged 10-19 years. Significant antibody titres were most prevalent in those aged 50 or older (21 %), followed by the age groups 20-29 years (7%), 30-39 years (6%) and 40-49 years (4%). The frequency distribution of reciprocal antibody titres is graphed in Fig. 2 and shows a bimodal distribution of titres with the first peak at titres of less than 1:16 and second peak at 1:128. 10
-
I(1029 Sera)
8
Seropositivity =4%
I
~
c:
CD
u ... 6
~
2
ISSN: 0003-4983 (Print) 1364-8594 (Online) Journal homepage: http://www.tandfonline.com/loi/ypgh19
Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines John H. Cross, Clarence Wheeling, Tirso Banzon, Virginia Basaca-Sevilla & Josue Sevilla To cite this article: John H. Cross, Clarence Wheeling, Tirso Banzon, Virginia BasacaSevilla & Josue Sevilla (1977) Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines, Annals of Tropical Medicine & Parasitology, 71:4, 435-441, DOI: 10.1080/00034983.1977.11687209 To link to this article: http://dx.doi.org/10.1080/00034983.1977.11687209
Published online: 15 Mar 2016.
Submit your article to this journal
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ypgh19 Download by: [Cornell University Library]
Date: 29 June 2017, At: 22:16
Annals of Tropical Medicine and Parasitology, Vol. 71, No. 4 (1977)
Amoebiasis and intestinal parasitic infections in a population on Cebu Island, the Philippines* Bv JOHN H. CROSS, CLARENCE WHEELING
U.S. Naval Medical Research Unit No. 2, Taipei, Taiwan TIRSO BANZON, VIRGINIA BASACA-SEVILLA
AND
JOSUE SEVILLA
The Bureau of Research and Laboratories, Philippine Health Department, Manila, Republic of Philippines Rectived 9 August 1976 Reports of epidemics of amoebiasis are not uncommon to public health authorities throughout the world and when investigated the reported increase in epidemic incidence often reveals misidentification of the parasite, Entamoeba histolytica, artefacts in stool specimens, or inaccurate diagnoses by inexperienced physicians. An increased reporting of cases may be authentic, however, and due to quite accurate diagnoses by technicians and physicians. We consider the present report an example of the latter. A private hospital located on the island of Cebu (Fig. I), Central Philippines, became concerned by the number of patients diagnosed as having intestinal amoebiasis. The Bureau of Research and Laboratories of the Philippine Health Department was informed and an investigation was carried out in July 1973 by a team of physicians, parasitologists and technicians from the Philippine Health Department and the U .S. Naval Medical Research Unit {NAMRU) No. 2. The investigation consisted of stool and serological examinations and a questionnaire survey. MATERIALS AND METHODS
Study Area The reporting hospital, operated by a large copper mining corporation, was staffed by well-trained physicians and laboratory personnel and provided care for approximately 7200 company employees and their families. The population of the surrounding barrio (village) was approximately 35 000 and the company was the major source of income for the entire area. Most of the labourers who worked for the company lived in the barrio, while the administrative and engineering staff were provided housing on the company compound. The water supply for part of the barrio came from an underground spring piped to outlets along the streets. Certain barrio subdivisions obtained chlorinated water piped from the company-owned deep wells while other water was from open or closed wells or small streams. Sanitation was excellent on the company compound, but in the barrio, toilet facilities consisted mostly of water seal toilets, outside privies or nearby fields.
* This study was supported through funds from the Bureau of Research and Laboratories, Philippine Health Department and the Naval Medical Research and Development Command, Navy Department, for Work Unit MR041.09.01-0146. The opinions and assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the Philippine Health Department, the U.S. Navy Department or the Naval Service at large. Reprint requests to Publication Office, NAMRU-2, Box 14, APO San Francisco 96263, or 7-1 Kung Yuan Rd., Taipei, Taiwan, ROC.
436
AMOEBIASIS ETC. ON CEBU, PHILIPPINES
Fig. 1. Map of the Philippine Islands showing Cebu and the area near Toledo where the survey was conducted.
Company houses were well constructed of wood or cement blocks, while barrio houses were of wood, cement blocks, bamboo or nipa. The terrain was rocky, with an elevation of approximately 1100 feet (335 m). The climate in this part of Cebu is relatively dry from November to April but wet for the rest of the year. The survey was carried out by asking company employees and their families to report to the hospital. All were volunteers; no attempt was made at random selection.
Serological Diagnosis Venous blood was obtained by vacutainer and sera separated by centrifugation and placed on dry ice. Sera were tested for E. histolytica antibodies by the microtitre adaptation of the
CROSS eta/.
437
indirect haemagglutination test (IHA) (Milgram et al., 1966) using antigens prepared from axenic cultures of the HK9 strain of the parasite (Thompson et al., 1968). Sera were inactivated at 56°C prior to testing and known positive and negative controls were used with each test series. Two-fold serial dilutions from I :4 to 1:8192 were tested and reciprocal antibody titres equal to or greater than I :128 were considered positive.
Parasitological Diagnosis Stool cartons were distributed to all participants and portions of the returned faecal specimens were placed individually in screw-capped vials containing 10% formalin and in vials containing polyvinyl alcohol (PVA). Consistency of the stool specimens and the presence of blood and mucus were recorded. Formalinized stool specimens were examined microscopically by direct and formalin-ether concentration (DFEC) methods and PVA specimens were smeared onto microscope slides, dried, stained with trichrome stain (PVAT) and examined microscopically. Each participant or a reliable third party was interviewed by a nurse or physician and a questionnaire completed relating to occupation, eating habits, toilet facilities water supply, animal contacts, history of diarrhoea and passage of mucus and blood in the stools. RESULTS
Serological Findings Sera were obtained from 1029 persons, 550 males and 479 females, aged 2-79 years; 43 or approximately 4% of the total tested had E. histolytica antibodies at titre ~ I :128. Overall, more male (28, 5%) than female (15, 3%) sera had positive antibody titres, but the distribution of seropositives by age group was variable. In those aged two to nine years 2% had antibodies, but titres were not detected in sera from those aged 10-19 years. Significant antibody titres were most prevalent in those aged 50 or older (21 %), followed by the age groups 20-29 years (7%), 30-39 years (6%) and 40-49 years (4%). The frequency distribution of reciprocal antibody titres is graphed in Fig. 2 and shows a bimodal distribution of titres with the first peak at titres of less than 1:16 and second peak at 1:128. 10
-
I(1029 Sera)
8
Seropositivity =4%
I
~
c:
CD
u ... 6
~
2
