Prevalence and Intensity of Infections of Ascaris lumbricoides and Trichuris trichiura and Associated Socio-demographic Variables in Four Rural Honduran Communities
Vol. 96(3): 303-314, April 2001
HM Smith, RG DeKaminsky**, S Niwas*, RJ Soto***, PE Jolly/+
Department of Epidemiology and International Health, School of Public Health *Biostatistics Unit, Comprehensive Cancer Center, University of Alabama, 1665 University Boulevard, Ryals Building, Room 217, Birmingham, Alabama 35294-0022, USA **Dirección de Investigación Cientifica, Unidad de Investigación Cientifica, Facultad de Ciencias Medicas ***Universidad Nacional Autonoma de Honduras, Tegucigalpa, Honduras
Between January and March 1998, a cross-sectional survey was carried out in four rural communities in Honduras, Central America. We examined the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infections among 240 fecal specimens, and the association between selected socio-demographic variables and infection for 62 households. The overall prevalence of A. lumbricoides and T. trichiura was 45% (95% CI 39.0-51.9) and 38% (95% CI 31.8-44.4) respectively. The most intense infections for Ascaris and Trichuris were found in children aged 2-12 years old. By univariate analysis variables associated with infections of A. lumbricoides were: number of children 2-5 years old (p=0.001), level of formal education of respondents (p=0.01), reported site of defecation of children in households (p=0.02), households with children who had a recent history of diarrhea (p=0.002), and the location of households (p=0.03). Variables associated with both A. lumbricoides and T. trichiura infection included: number of children 6-14 years old (p=0.01, p=0.04, respectively), ownership of a latrine (p=0.04, p=0.03, respectively) and coinfection with either helminth (p=0.001, p=0.001, respectively). By multivariate analysis the number of children 2-5 years living in the household, (p=0.01, odds ratio (OR)=22.2), children with a recent history of diarrhea (p=0.0, OR=39.8), and infection of household members with T. trichiura (p=0.02, OR=16.0) were associated with A. lumbricoides infection. The number of children 6-14 years old in the household was associated with both A. lumbricoides and T. trichiura infection (p=0.04, p=0.01, OR=19.2, OR=5.2, respectively).
Key words: intestinal helminths - Ascaris lumbricoides - Trichuris trichiura - prevalence - intensity - risk factors - Honduras
Intestinal parasites remain a major health problem in many developing countries. The World Health Organization (WHO) estimated that there were 1000 million cases of ascariasis due to Ascaris lumbricoides, and 500 million cases of Trichuris trichiura infection worldwide (WHO 1987). In 1994, Chan et al. (1994c) estimated that worldwide there were 1471 million and 1048 million cases of A. lumbricoides and T. trichiura infections, respectively. Clinically, A. lumbricoides can cause blockage of the intestine and T. trichiura has been associated with dysentery (Cooper et al. 1992). Both helminths have also been associated with stunted growth (Cooper & Bundy 1988, Stephenson et al. 1989, 1993, Adams et al. 1994, Simeon et al. 1995, Hadju et al. 1996, 1997, Saldiva et al. 1999) and impaired cognitive functions in children (Nokes et al. 1992a, b, Oberhelman et al. 1998). Another common soil transmitted helminth that causes severe morbidity and is often found with A. lumbricoides and T. trichiura infections is hookworm (WHO 1987). However, hookworm infection will not be included in this research since the method used (Kato thick smear) for detecting eggs in the study was not suitable for recovery of hookworm eggs.
Countries in Central America, such as El Salvador, Guatemala, and Honduras, have a high prevalence of parasitic infections. A survey of intestinal parasites in children with diarrhea in El Salvador, demonstrated that 18% of the children were infected with A. lumbricoides and 31% with T. trichiura (Reinthaler et al. 1988). In Guatemala, 41% of the population in a rural village was infected with A. lumbricoides and 60% with T. trichiura (Anderson et al. 1993). Data from 14 public health laboratories in Honduras for 1991 showed A. lumbricoides infections in people of all ages ranging from 70% in Tocoa at the northern coast to 5% in Nacaome, near the Pacific coast. Percentages of individuals infected with T. trichiura were lower, ranging from 32% to 1% in the above mentioned areas (Kaminsky 1996a).
Although many studies regarding intestinal parasites focus on establishing the prevalence and intensity of these infections in different populations, fewer studies have examined the socio-cultural factors that affect transmission of intestinal helminths. Some studies have shown that the lack of education, lack of latrines, occurrence of diarrhea, lower socio-economic status, inadequate disposal of human excreta and the level of sanitation in households are related to parasitoses (Cooper & Bundy 1988, Holland et al. 1988, Yasuf & Hussain 1990, Rajeswari et al. 1994, Tshikuka et al. 1995, Ighogboja et al. 1997, Mahfouz et al. 1997, Pegelow et al. 1997, Gamboa et al. 1998). These reports coupled with the fact that there have been few surveys designed to determine associations between socio-cultural variables and intestinal helminth prevalence data prompted us to initiate this study in four rural Honduran communities.
In this study, we collaborated with Project UNIR (unite) based at the Panamerican Agricultural School (Escuela Agricola Panamericana- EAP), El Zamorano. The School is located in the Zamorano Valley, 40 km from Tegucigalpa, the nation's capital and was very willing and helpful in providing the necessary facilities and accommodations for one of us (HMS). Project UNIR is an organization at the EAP that was established in 1996. Its principal goals are both rural development and land conservation. We studied the prevalence and intensity of Ascaris and Trichuris infections in individuals of all ages in four communities under UNIR, and identified variables that have an important association with such infections.
ACKNOWLEDGEMENTS
To Eduardo Aguilar and Suyapa Meyer for all their help at the Escuela Agricola Panamericana. To the staff and students of the Project UNIR, and Dr Luis Castellanos at the Pan American Health Organization for his suggestions. To Dr Ed Cupp, Dr Richard and Ms Marie Hudspeth, Dr Curtis Jolly, Dr Jerold Theis and Dr Heidi Weiss for reviewing the manuscript. To the people of El Llano, El Chaguite, Santa Ines, and El Chaguite-Belen for their cooperation in this survey.
Fig. 1 | Fig. 2 | Fig. 3 | Table I | Table II | Table III | Table IV
This study was supported by the Sparkman Center for International Public Health Education, University of Alabama at Birmingham School of Public Health, the Universidad Nacional Autonoma de Honduras, and the Escuela Agricola Panamericana, Honduras.
+Corresponding author. Fax: 205-975-3329. E-mail: jollyp@uab.edu
Received 31 August 2000
Accepted 4 October 2000
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