The prevalence of intestinal parasitic infections among schoolchildren in Colalao del Valle, a high-altitude community in Tucumán province, Argentina, was investigated. The data revealed a high prevalence of parasitism (79.7%) with no significant differences in distribution by sex or age. Protozoa infections were the most common with Blastocystis hominis being the most prevalent (62.5%), followed by Giardia lamblia (29.7%), Endolimax nana (15.6%), Entamoeba coli (12.5%) and Iodamoeba bustchili (3.1%). Interestingly, there was an absence of soil-transmitted helminths among the studied population which could be related to climate (variable temperatures, moderate rainfall) and soil type (clay).Fil: Dib, Julian Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Fernandez Zenoff, Maria Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Oquilla, Juana del Valle. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Rudelli, M.. Ministerio de Salud de la Nación; ArgentinaFil: Lazarte, S.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Gonzalez, Silvia Nelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin

Dib, Julian Rafael

Fernandez Zenoff, Maria Veronica

Gonzalez, Silvia Nelina

Lazarte, S.

Oquilla, Juana del Valle

Rudelli, M.

English

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

800Tropical Biomedicine 32(4): 800–804 (2015)Research NoteParasitological survey of schoolchildren from a high-altitude community from Tucumán Province, Argentina:Remarkable low detection of soil-transmitted helminthsin comparison with coastal communitiesDib, J.R.1,2*, Fernández-Zenoff, M.V.1,2, Oquilla, J.1, Rudelli, M.4, Lazarte, S.1 and González, S.N.1,31Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456,(4000) Tucumán, Argentina2PROIMI-CONICET, Av. Belgrano y Pje. Caseros, (4000) Tucumán, Argentina3CERELA-CONICET, Chacabuco 145, (4000) Tucumán, Argentina4Equipos Comunitarios para Pueblos Originarios, Programa Nacional Médicos Comunitarios, Ministerio deSalud de la Nación, Argentina*Corresponding author email: jdib@fbqf.unt.edu.arReceived 17 October 2014; received in revised form 27 December 2014; accepted 29 December 2014Abstract. The prevalence of intestinal parasitic infections among schoolchildren in Colalaodel Valle, a high-altitude community in Tucumán province, Argentina, was investigated. Thedata revealed a high prevalence of parasitism (79.7%) with no significant differences indistribution by sex or age. Protozoa infections were the most common with Blastocystishominis being the most prevalent (62.5%), followed by Giardia lamblia (29.7%), Endolimaxnana (15.6%), Entamoeba coli (12.5%) and Iodamoeba bütschlii (3.1%). Interestingly, therewas an absence of soil-transmitted helminths among the studied population which could berelated to climate (variable temperatures, moderate rainfall) and soil type (clay).Although most of the studies about intestinalparasite prevalence are normally conductedin populations situated at sea level, severalsurveys have been performed amongcommunities who live in high-altitude places.Interestingly, parasite prevalence rates haveshown to be affected by altitude-relatedfactors such as climate, soil quality, moisture,etc. (Appleton & Gouws, 1996; Appleton etal., 1999; Mabaso et al., 2003).Little is known about the distributionof enteroparasitosis in high-altitudecommunities in Argentina, and to ourknowledge, most of the studies performed inTucumán province have been conducted inpopulations living near sea-level (Valpergaet al., 1979; Silvia et al., 2006; Dib et al., 2012;2014).The current study area is Colalao delValle, a mountain town located at 1,815 mabove sea level (a.s.l.), in Tucumán province,202 km from the capital city, within latitudesof 6° 30’ and 6° 40’ N, longitudes 3° 40’ and3° 50’ E. The town is a rural community witha population of 1,207 who are predominantlysubsistence farmers (Figure 1). The climateis primarily desert, with an average annualtemperature of 14ºC and large diurnaltemperature variations. The average annualrainfall is 200 mm, with rainy summers anddry winters. The soils in this area areclassified as entisol and aridisol, which arecharacteristic of arid and semi-arid climates.While entisols are defined by the absence ornear absence of horizons (layers), aridisolsare characterized by low organic content, by801water deficiency and by a significantaccumulation of translocated layer, silicateclay, soluble salts, or sodium ions (Soil SurveyStaff, 1999).This town has three public primaryschools, one public secondary school and apublic primary health care centre. The villagehas piped water provided by a public utility.The supply system gets water from anunderground aquifer and is disinfectedthrough chlorination. Sewage or waterdisposal facilities used by most inhabitantsinclude a water closet with septic chambers.A small number of families have pit latrinesand only two houses had open defecation.Garbage is collected twice a week, a serviceprovided by the local government, andgarbage disposal is an open pit and is locatednear the secondary school.Our research focused on primaryschoolchildren, who are commonly a high-risk group with the highest infection rates.Previous clinical studies among thispopulation have shown the presumptivepresence of parasitic diseases with symptomsincluding: anal itching, abdominal pain,sleeping disorders, diarrhoea, vomiting,appetite loss, weakness, and inexplicablefever, but to our knowledge no previoussurveys were done.The protocol for this study was approvedby the Ethics Committee of the NationalUniversity of Tucuman (UNT), Argentinabefore commencement. The participantswere informed that the procedure used didnot pose any potential health risks and theiridentities and personal information wouldbe kept strictly confidential. During themeetings, parents and their children wereinformed that their participation wasvoluntary and they could withdraw from thestudy at any time without giving legitimatereason. Consent of those who agreed toparticipate was taken in written form (signed)by their parents or guardians (on behalf oftheir children).The study was performed between Juneand November of 2011. The Nº 32 Colalaodel Valle School has 108 children of which70, distributed in 43 families, showedsymptoms related to enteroparasiticinfection. Twenty samples were remitted toFigure 1. A traditional adobe house in Colalao del Valle (Tucumán province, Argentina),showing the typical living conditions of the community inhabitants.802the laboratory. The Nº 42 El Arbolar Schoolhas 54 children, 39 showed signs of intestinalinfection and they were distributed among25 families. Twenty samples were remittedto the laboratory. In Nº 325 El Bañado School64, with 78 students, had presumptiveparasites and 24 samples were sent to thelaboratory (Table 1). Selected schools werebetween 7 and 15 km (mean 11 km) apartand served children of a similar socio-economic status.Each child was provided with two bottlescontaining 5% buffered formalin, one forserial parasitological study and the other foranal swabs. Five anal swabs from each childwere collected during a time frame of fiveconsecutive days, using sterile gauzes bycleaning the perianal zone in the morningimmediately after getting up and stored insterile containers.In total, faecal samples were collectedfrom 64 children (38 males and 26 females)aged between 4-13 years. Samples wereanalysed in the lab station by direct smearafter being concentrated by the modifiedRitchie method (Melvin & Brooke, 1982). Thesediments were stained by lugol or carbol-fuchsine and observed by optical microscopy.In addition, the containers containing thegauzes were vigorously shaken and then, withthe aid of a glass rod, the squeezed gauzeswere removed. The content of each containerwas centrifuged at 500 ×g for 10 min and theobtained sediment was observed underoptical microscopy. The results wereconveyed to school authorities and theparents. The National Health Serviceprovided antiparasitic treatments to theinfected children.The relationship between the proportionsof intestinal parasites with sex was analyzedby the chi-square test and with age by theMann-Whitney U test. A p-value of less than0.05 was considered statistically significant.In addition, microbiological analysis oftap water and a reservoir from the watertreatment plant were carried out by theBacteriology Laboratory from the NationalUniversity of Tucuman, following standardmethods and parasitological analysis wasperformed using a flocculation method (Veseyet al., 1993).Although containers were given to thetotal school population (240), only 26.66%(64) of them were sent back to the laboratory,as shown in Table 1. The frequency of infectedchildren in the present study was 79.7%(Table 2). A total of seven parasitic specieswere recorded: five protozoa and twonematodes. Protozoa infections were themost common. Prevalence over the 64samples studied was as follows: Blastocystishominis (62.5%), Endolimax nana (15.6%),Entamoeba coli (12.5%), Giardia lamblia(29.7%) and Iodamoeba bütschlii (3.1%).Among helminths, only Ascaris lumbricoidesand Enterobius vermicularis were detected,the latter being the most frequent (23.3%)(Table 2). No significant differences indistribution by sex or age were found(p>0.05). In the studied population, 37.5% ofthe positive samples showed one parasite,20.3% showed two parasites and 21.9% threeor more parasites.The results presented in this work areconsistent with other studies conducted inTucumán province where up to 86.6% ofprimary schoolchildren from different ruralTable 1. School population analyzed in the Colalao del Valle communitySchoolSchool Symptomatic Family SamplingPopulation children groups sizeNº 32 Colalao del Valle 108 70 43 20Nº 42 El Arbolar 54 39 25 20Nº 325 El Bañado 78 64 ND* 24Total 240 173 – 64* ND: not determined.803regions were infected (Silvia et al., 2006; Dibet al., 2012; 2014).A quite remarkable observation in thishigh-altitude community is the completeabsence of soil-transmitted helminths (STH)among studied children. A previous surveyconducted in Famaillá city (Tucumán),located more than 1,000 m lower in altitudeand around 100 km away from Colalao delValle and with comparable socio-economicand sanitary conditions, has shownsignificant infections prevalent of STH:Ascaris lumbricoides (20.8%), Trichuristrichiura (12.8%), and Strongyloidesstercoralis (2.7%) (Dib et al., 2012). On theother hand, the prevalence of protozoa wassimilar to previous studies in the sameprovince (Valperga et al., 1979; Silvia et al.,2010; Dib et al., 2012; 2014).Although we report here one patientinfected with A. lumbricoides, the micro-scopic analysis indicated the presence ofonly infertile eggs, which cannot becomeinfectious. This child could have acquired theinfection some time ago or may have been inareas with a high-rate of infection, not far fromthere, but at lower altitudes.This atypical STH prevalence could beexplained by environmental or climaticvariables, including soil type and moisture,rainfall and temperature, which affectecological requirements for the parasitictransmission of geohelminths (WHO, 1964).This was found in earlier studies whichshowed that a higher prevalence inhookworm infection is limited to areas lowerthan 150 m a.s.l., sandy soils with a claycontent of less than 15%, warm temperaturesand relatively high rainfall (Mabaso et al.,2003). Studies carried out in KwaZulu-Natal,South Africa, indicated that Necatoramericanus and Strongyloides stercoralisinfections occurred only in the coastallowlands whereas those of Trichuristrichiura and A. lumbricoides occurred athigher altitudes, about 1,500 and 1,700 m a.s.l.(Appleton & Gouws, 1996; Appleton et al.,1999). Apparently, the ecological andenvironmental features in Colalao delValle, mostly altitude-related, are quitedisadvantageous for the transmission of thefree-living stages of nematodes normallyfound in other areas of the province.In relation to microbiological analysesof the drinking water, no parasitic elementswere found (eggs, larvae, cysts ortrophozoites) possibly due to the lowsensitivity of the method used. However,bacteriological analyses showed that thewater was not suitable for humanconsumption. At the time when our study wasdone, water chlorination was stopped dueto lack of a power supply.Even though a reduction in the impact ofhelminths on the studied community wasobserved, possibly due to environmentalconditions, a high prevalence of protozoa wasfound. The quality of drinking water shouldbe improved and local sanitary authoritiesshould take action on this matter.Despite the relatively small populationstudied, our results shed light on a ratherunexplored and undefined issue in Argentina,the epidemiology of intestinal parasites inhigh-altitude communities. Currently, we areexpanding our studies to neighbouringpopulations in order to have a broader ideaof the distribution and impact of protozoa andSTH in such elevated areas.Acknowledgments. The authors are gratefulto the personnel working at these schools fortheir support and assistance. CIUNT D429financially supported the research. We thankto Tom Haran and Dr. John Paluszynski forhelpful technical discussions and Englishediting of the manuscript.Table 2. Distribution of parasites in the studiedpopulationParasite Prevalence (%)ProtozoaBlastocystis hominis 62.5 (40/64)Giardia intestinalis 29.7 (19/64)Entamoeba coli 12.5 (8/64)Endolimax nana 15.6 (10/64)Iodamoeba bütschlii 3.1 (2/64)HelminthsAscaris lumbricoides 1.6 (1/64)Enterobius vermicularis 23.3 (15/64)804REFERENCESAppleton, C.C. & Gouws, E. (1996). Thedistribution of common intestinalnematodes along an altitudinal transectin KwaZulu-Natal, South Africa. Annal ofTropical Medicine and Parasitology 90:181-188.Appleton, C.C., Maurihungirire, M. & Gouws,E. (1999). The distribution of helminthinfections along the coastal plain ofKwaZulu-Natal province, South Africa.Annal of Tropical Medicine andParasitology 93: 859-868.Dib, J.R., Fernández-Zenoff, M.V., Oquilla, J.,Lazarte, S. & González, S.N. (2014).Prevalence of intestinal parasiticinfection among children from a shantytown in Tucuman, Argentina. TropicalBiomedicine (In press).Dib, J., Oquilla, S.G., Lazarte, S. & Gonzalez,S.N. (2012). Parasitic prevalence in asuburban school of Famaillá, Tucumán,Argentina. ISRN Microbiology, Article ID560376, 4 pages.Mabaso, M.L.H., Appleton, C.C., Hughes, J.C.& Gouws, E. (2003). The effect of soil typeand climate on hookworm (Necatoramericanus) distribution in KwaZulu-Natal, South Africa. Tropical Medicineand International Health 8(8): 722-727.Melvin, D.M. & Brooke, M.M. (1982).Laboratory procedures for the diagnosisof intestinal parasites. In: LaboratoryTraining and Consultation Division,Centres for Disease Control (Editors,DHEW Publication [CDC] 3rd Edition) pp.82 - 8282, Atlanta, Ga, USA.Silvia, G.L., Christian, A., Juana, O. & Silvia,N.G. (2006). Alarming levels of infectionby enteric parasites in children ofBurruyacu, Province of Tucumán,Argentina. International Journal ofTropical Medicine 1: 40-43.Smith, G. (1990). Ecology of the free-livingstages: a reappraisal. In: HookwormDisease: Current Status and NewDirections (Editors, G.A. Schad & K.S.Warren) pp. 98 – 104. Taylor and Francis,London, UK.Soil Survey Staff (1999). Soil taxonomy: Abasic system of soil classification formaking and interpreting soil surveys. In:USDA-NRCS Agriculture Handbook 436(second edition) p. 869. Washington, D.C.,U.S.Valperga, S.M., Pérez, L. & Nava, C.A. (1979).Helmintiasis intestinales en habitantesdel ex departamento Famaillá (Provinciade Tucumán). Revista de la Facultad deMedicina Tucumán 12: 18-24.Vesey, G., Slade, J.S., Byrne, M., Shepherd, K.& Fricker C.R. (1993). A new method forthe concentration of Cryptosporidiumoocysts from water. Journal of AppliedBacteriology 75(1): 82-86.World Health Organization (1964) Soil-transmitted helminths. Technical ReportSeries No. 277, Geneva.

Parasitological Survey of Schoolchildren from a High-Altitude Community from Tucumán Province, Argentina. Remarkable Low Detection of Soil-Transmitted Helminths in Comparison with Coastal Communities

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Parasitological Survey of Schoolchildren from a High-Altitude Community from Tucumán Province, Argentina. Remarkable Low Detection of Soil-Transmitted Helminths in Comparison with Coastal Communities

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