Intestinal parasitosis among the elderly people in Kathmandu Valley
Bikash Shakya,1 Shiba Kumar Rai,2,3 Anjana Singh1 and Arina Shrestha1
1Central Department of Microbiology, Tribhuvan University, Kathmandu Nepal; 2Nat'l Institute of Tropical Medicine
and Public Health Research; 3Department of Microbiology, Nepal Medical College, Kathmandu, Nepal
Corresponding author: Prof. Dr. Shiba Kumar Rai, Nat'l Institute of Tropical Medicine and Public Health
Research, Narayangopal Chowk Shankha Marga, Kathmandu, Nepal;
Present study was carried out among the elderly people (60+ years of age) from August 2005 to July
2006 in Kathmandu Valley to assess the prevalence of intestinal parasitosis in them. Stool samples
were collected from 235 elderly people (122 from government elderly home, 66 from private elderly
home and 47 from the households in a rural community). The samples were examined by formal
ether sedimentation and Sheather's sucrose floatation followed by Kinyoun's modified Ziehl-Neelsen
staining. The overall prevalence of intestinal parasites was found to be 41.7%, out of which 30.6%
had multiple parasitism. The government elderly home had significantly higher parasitic prevalence
(50.8%) followed by the rural community (46.8%) and the private elderly homes (21.2%) (P<0.05).
Males (43.8%) had slightly infection rate than females (40.4%) (P>0.05). There was equal infection
rate with protozoa (25.8%) and helminths (27.0%). Trichuris trichiura (39.4%) and Entamoeba
histolytica (19.7%) were the commonest helminth and protozoa, respectively.
Keywords: Elderly people, elderly homes, intestinal parasites, Kathmandu.
Parasitic disease is a major public health problem in developing countries. WHO has estimated that
Ascaris lumbricoides, hookworm and Trichuris trichiura infect 1.4 billion, 1.3 billion and 1.0 billion
people worldwide, respectively.1 The protozoan parasites although being less common are associated
with the highest number of mortalities.2
Children being the major victim of the infection, most of the researches in intestinal infections are
concerned with pediatric age group. However, these infections have been found to be common even
among the elderly people. Gastrointestinal problems have been reported as the most common health
problems of elderly people in Bangladesh and Myanmar and a leading cause of death.3 Diarrhoea has
been recognized as the commonest cause of hospitalization among the elderly people in Thailand. In
India too, it is one of the top ten causes of hospitalization and death.3 In Brazil and Central America,
the reported prevalence of intestinal parasitosis among 60+ people were 3.8% and 48.0%,
respectively.4,5 In Bangladesh, Malayasia and China, the prevalence has been found 50.0%, 28.4%
and 51.26%, respectively among 50+ people.6-8
Owing to poor sanitary and other living conditions of majority of Nepalese families, the elderly
members could be the major victim of these infections. Earlier studies in Nepal have revealed
gastrointestinal complain as the major health complain of old people.9,10 The physical disability and
less effective self care during old age lead to insufficient sanitary practice and poor personal hygiene
which make old people more susceptible to gastrointestinal infections. The elderly have a
predisposition to infectious diarrhoea. This predisposition could result from several factors including
age related immune system dysfunction, achlorhydria, altered intestinal or colonic motility and
changes in fecal flora.11 Institutionalization of elderly people significantly increases the risk of
infection from common source outbreaks such as food-borne epidemics and by person to person
spread.12 In this paper, we report the prevalence and the pattern of intestinal parasitic infection
among the elderly people in Kathmandu Valley.
MATERIALS AND METHODOLOGY
Study population and sample collection: The stool samples were collected from the people above 60
years from a government and five private elderly homes and from the households in a rural
community of the valley.
Processing of the samples: The samples were examined by formal ether sedimentation and
Sheather's sucrose floatation followed by Kinyoun's modified Ziehl-Neelsen staining. The
identification of the cysts, trophozoites, eggs, larvae and oocysts of the parasites was done based on
their basic morphology under microscope
Statistical analysis: Chi-square test was used to evaluate apparent differences for significance.
Association of intestinal infections with different variables was tested.
Out of 235 stool samples collected, 98 (41.7%) samples had one or more intestinal parasites. Of the
98 positive samples, 68 (69.4%) samples yielded single parasite, where as 30 (30.6%) samples had
multiple parasites (Table 1). Among 3 study groups, the highest positive rate was found in
government run elderly home (50.8%) followed by rural community (46.8%) and private elderly
homes (21.2%) (P<0.05). The average positive rate in elderly homes was 40.4%. The parasite
infection rate among male and female was found to be 43.8% and 40.4%, respectively (P>0.05) (Fig
Out of 235 elderly people studied, 28.9% had monoparasitosis and 12.8% had multiparasitosis. No
difference in multiparasitic and monoparasitic infection rates in two genders was observed
(multiparasitosis: 30.8% in males and 30.5% in females; monoparasitosis: 69.2% in males and
69.5% in females).
The helminth and protozoan infection rates in males 27.0% and 25.8%, respectively. Similar trend
was observed among females (helminth 24.0% and protozoa 21.9%) (P>0.05). Of the parasites
detected, 54.5% were helminths and 45.5% were protozoa. The government run elderly home had
helminthic and protozoal infection rates of 51.8% and 48.2%, respectively. Similarly, in the
community, 74.2% helminths and 25.8% protozoa were detected among total infected. In contrast to
these, the helminthic and protozoal infection rates in the privately run elderly homes were 31.3% and
68.8 %, respectively (Table 2).
In the present study, about two-fifth of the elderly people were found to be infected with one or more
intestinal parasites. This finding was much higher than that observed in Brazil (60+ people),5
Malayasia (50+ people)7 and Iran (69+ people).13 In contrast, studies done among 50+ people in
China8 and Bangladesh6 have shown higher prevalence (51.3% in China and 50% in Bangladesh).
These findings may correlate with the prevalence of parasitosis among the general population of the
particular geographical area.
In Nepal, the prevalence ranges from 27.0% to 76.4% in different studies carried out among general
population in different geographical areas.14-17 The similarity of the study-result with the current
trends of intestinal infection in the country may be due to the equal susceptibility of the elderly
people towards the infections as the other age groups. However, illiteracy, poor living standard,
poverty, improper hygiene, unsafe drinking water etc. might be the causes behind the increased rate
of the parasitic infection among the elderly people in this study, as compared to the infection rate
among the people of similar age group elsewhere.
Of the three study groups, the highest parasitic infection rate found in the government elderly home
followed by community and private elderly homes appeared to be associated with the crowdedness,
level of sanitation and degree of care provided. A relatively lower prevalence in the private elderly
homes appeared to be associated with relatively better living condition. In one of the elderly homes,
there was a provision of even single room per person and boiled drinking water. The parasitic
infection rate seen in the community was quite closer to that of government elderly home, which
reflected the relatively poor living status of Nepalese elderly people in the rural region even in the
vicinity of the capital city.
The nearly equal parasitic infection rate found between two genders was in agreement with the trend
observed by other studies in Nepal15,16 and elsewhere in the world.7,13 In contrary, males have been
found to be infected significantly at higher rate in Brazil.5 Similarly, a study from Nepal18 and few
studies from elsewhere8,19 have shown higher infection among female.
Female were found to have 1.25 times more chances of being infected with A. lumbricoides than the
male.20 This indicated that the gender may or may not play role in parasitosis depending on the
region and other environmental or behavioral factors. Generally, the increased mobility of the male
increases the risk of infection among them, while the involvement of female in childcare and their
low educational status is responsible for increased risk in them. Elsewhere, female reportedly have
more soil contact during growing vegetables and eat raw vegetable with prepared food more often
than males.20 However, in this study, this was not true.
The ratio of monoparasitism and multiparasitism among total infected people (7:3) was consistent
with the rate among general population in Brazil5 and Lao PDR.20 In the contrary, the
multiparasitism rate was higher in Fujian Province (China) in 1998 and lower in the same place in
1999.8 In Nepal, the rate of multiparasitism varies greatly in study populations and geographical
areas.16,17 Very low rate of multiparasitism (<5.0%) has been reported in one of the hilly regions in
eastern Nepal.17 Whereas, a report has shown very high rate (63.2%) in western Nepal, male being
the common victim of multiparasitism.16 However, in this study, rates of monoparasitism and
multiparasitism were found to be independent of the gender of the elderly people.
The rate of helminthic infection was almost equal to the rate of protozoal infection with no marked
difference in two genders. However, other studies among general population in Nepal have found
higher prevalence of helminthic infection.16,18 Similarly, Oda et al has reported protozoa more
among males than in female and explained to be due to genetic and physical factors.21 Among the
individual study groups, the higher helminthic infection rate in the community observed in this study
might be due to the presence of more open land and agriculture as the major occupation of the
people in the rural community, while water may be the cause behind higher protozoal infection rate
in private elderly home.
T. trichiura detected as the commonest parasite in the study, infecting almost two-fifth of the total
infected elderly people was similar to the finding of Chai et al 22 among the people of same age
group but the rate of infection was lower. T. trichiura has been reported as the commonest helminth
also elsewhere in the world.7,19 This might be due to incomplete removal of this helminth with a
single dose of anti-helminthic drug, particularly in heavy infection.23 However, very low T. trichiura
infection rate has been reported among 45 + people by Blangero et al24 in a specified community of
Nepal. The infection rate of just around one quarter of the total infected people aged above 50 years
has been reported in Brazil.5
Quite lower infection rate by A. lumbricoides in the study was in agreement with prevalence of the
helminth observed among 40+ people in Iran.13 However, Ascaris has been reported as the
commonest parasite among general population15-17 and among hospital visiting patients in Nepal
during a period of ten years.18 In this study, the prevalence of hookworm infection was marginally
higher than that of A. lumbricoides but very low as compared to T. trichiura infection rate as
reported in Lao PDR.20 On the other hand, higher prevalence of hookworm infection has been
reported among 45+ people in specified communities in Nepal24 and 50+ people elsewhere in the
In contrary to the finding of G. lamblia as the commonest protozoa among different age groups in
Nepal,21 E. histolytica has been found to be the commonest one in this study. Elsewhere, Endolimax
nana has been reported as the commonest protozoa among 60+ people.5 Very low prevalence of E.
histolytica infection has been reported among 40+ people in Iran13 and the healthy elderly in India.26
Infection with E. histolytica is common in inhabitants of developing countries; it predominantly
affects people with poor socioeconomic conditions, poor hygienic practices, and malnutrition. In this
study, the prevalence rate of E. coli was found to be somewhat lower than the finding among 60+
people in Brazil.5 However, Rai et al has reported E. coli as the commonest protozoa in a western
district of Nepal.16
Very low prevalence of G. lamblia observed in this study was in agreement with the findings of
Gambhir et al26 among healthy Indian elderly people indicating the risk of infection with G. lamblia
to decrease with ageing.27 As a reaction to infection with Giardia, both humoral and cellular immune
response generated by host secretary IgA and IgM appear to play role in clearance of intestinal
infection. This gives some degree of protection against reinfection.21 So, the chronically exposed
people, especially elderly group have lower attack rate. However, greater prevalences of G. lamblia
have been reported among 40+ people in Iran.13
Very low prevalence (0.8%) of C. cayetanensis found in this study might be due to the immunity
developed after repeated attack28 This finding was much lower than the finding of Kimura et al
(9.2%) reported in Nepal.29 Similarly, a higher rate of cyclosporosis was observed in young and
elder adults up to 60-year-old in Peru.30 An ongoing study in Nepal has revealed C. cayetanensis at
significant rate from the vegetables, particularly the green onion (personnel communication).
C. parvum is generally found to infect the immunocompromised hosts including the elderly people.
The prevalence rate of C. parvum found in this study was quite consistent with the findings of Lee et
al 31 among 60+ people. Elderly people are reportedly at higher risk of C. parvum infection.32
Comparatively, higher prevalence of C. parvum have been reported among elderly people
elsewhere.31-33 Cryptosporidiosis among the elderly people without immunocompromised status may
be due to the higher prevalence of the organism in the environment.26 Higher rate of C. parvum
infection (5.2%) has been reported among HIV victims in Nepal.34 Cryptosporidiosis has been found
to be positively associated with diarrhoea.26 In this study also, around one-fourth of the subjects with
diarrhoea had C. parvum.
Thus, present findings showed that the elderly people in the developing countries like Nepal are
under significant threats of the intestinal parasitic infections and the related morbidities. The
condition can be remarkably improved by availing them with appropriate nutrition, safe drinking
water, hygienic living conditions, periodic health check-ups and the regular deworming. Beside
these, raising awareness among the elderly through the health education programmes can be an
The authors are grateful to the senior citizens who volunteered in the study and would like to thank
Nabaraj Adhikari, Jyoti Pant, Anil Shrestha and Pragya Sharma for their cooperation during the
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Table-1: Pattern of parasitic infections in elderly people
Type of infection Total Percentage
Single parasite 68 69.4
Protozoa 34 34.7
Helminth 34 34.7
Multiple parasite 30 30.6
Protozoans 5 5.1
Helminthes 9 9.2
Protozoans + Helminthes 16 16.3
Total 98 100.0
Fig. 1 Distribution of parasites in two genders of different study groups (n=235)
Table-2: Frequency of the parasites detected in different study groups Download full-text
Hookworm 6 (7.1%)
Total Protozoans 41 (48.2%)
Total Parasites 85
Elderly people at
Private elderly homeCommunity
Fig. 2. Distribution of protozoal and helminthic infections in two genders.