ORIGINAL

Niger J Paed 2014; 41 (3):204 –208

Musa S

Yakubu AM

Olayinka AT

Prevalence of Cryptosporidiosis

in diarrhoeal stools of children

under-five years seen in Ahmadu

Bello University Teaching

Hospital Zaria, Nigeria

DOI:http://dx.doi.org/10.4314/njp.v41i3,10

Accepted: 14th February 2014

Abstract: Introduction: Human

cryptosporidiosis is a zoonotic dis-

ease and is increasingly recognized

as a major public health problem. It

is associated with significant

effects on growth, physical and

cognitive functions and excess

mortality especially among chil-

dren.

Aim: To determine the prevalence

of Cryptosporidium oocyst excre-

tion in children less than 5years

with diarrhoea in ABUTH Zaria.

Methods: Children aged 0 to 59

months managed in paediatrics

wards of ABUTH for diarrhoea

were studied between July 2008

and June 2009. Stool specimens

obtained from these subjects were

analysed for Cryptosporidium oo-

cysts using the modified ZN stain-

ing technique.

(42.2%) boys and 107(57.8%)

girls. A total of 33 children studied

excreted oocysts in their stools,

giving a prevalence of Crypto-

sporidium oocysts of 17.8%. The

highest rate (21.7%) was observed

in children aged between 13 and

36 months, and no oocysts were

observed in stools of neonates.

Oocyst excretion was observed to

be commoner in the rainy season.

Conclusion: Cryptosporidium is a

common cause of diarrhoea among

under-five children in our environ-

ment. It was commoner after in-

fancy and in the rainy season.

(

)

Musa S

Yakubu AM

Department of Paediatrics,

Olayinka AT

Department of Medical Microbiology,

Ahmadu Bello University Teaching

Hospital, Zaria, Nigeria.

Email: musa4all@gmail.com

Recommendation: Routine screen-

ing for Cryptosporidium should be

part of evaluation of diarrhoeal

illness especially in children be-

yond the neonatal age group.

Results: A total of 185 children

were enrolled. There were 78

Key words: Cryptosporidiosis;

diarrhoea; under-five; children

Introduction

stools of under-five children to range between 6.0% and

6,8

7

.7% . A prevalence of 8.1% was reported among

11

Cryptosporidium spp. is one of the leading causes of

severe diarrhoea . It is said to be the third or fourth com-

monest cause of diarrhoeal disease, and its prevalence is

much higher in developing countries than elsewhere .

It has been described as an emerging infectious threat ,

with dire consequences including prolonged hospitaliza-

under-five children in Addis Ababa . Reports from

northern Ghana showed that Cryptosporidium oocysts

was found only sporadically in both patients and

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2

,3

12

controls . In Nigeria, the prevalence of

1

Cryptosporidium oocystsin st₁o₃o_,₁l₄samples in Enugu

varied between 12.5%and 29% . The prevalence was

4

15

16

tion, adverse effect on the weight gain of children , s₅e_,-₆

10.8% in Port Harcourt and 14% in Ilorin . In one

vere effects on growth and nutritional status

report from south west Nigeria, Cryptosporidium oocyst

7

17

diminish₈ed cognitive function and may ultimately lead

was not found in stool samples of patients studied , but

to death .

a more recent study showed that Cryptosporidium is the

most prevalent intestinal pathogenic parasite in Lagos,

1

8

It is a zoonotic disease with mainly bovine and human

reservoirs . Several reports from parts of the developing

especially among diarrhoeal cases .

3

world suggest cryptosporidiosis is endemic and is one of

the most common causes of persistent diarrhoea among

children, being as₉s_,o₁₀ciated with more than a quarter of all

diarrhoeal illness . Prospective community studies of

childhood diarrhoea conducted in Guinea Bissau, found

prevalence of Cryptosporidiumoocysts in diarrhoeal

While several workers had previously identified Crypto-

sporidiosis to be an₁₃i_-₁m₆_,₁p₈ortant cause of diarrhoeal illness

in parts of Nigeria

there are no studies focussed on

the prevalence of Cryptosporidium oocysts excretion in

diarrhoeal stools of under-five children in this commu-

nity. This study was therefore undertaken with a view to

2

05

determining the prevalence of Cryptosporidium oocysts

excretion in diarrhoeal stools of children less than five

years presenting to ABUTH Zaria. This will assist in

formulating recommendations for the management and

prevention of the condition in our environment.

or improvement of nutrition.

Ethical Consideration: Approval of the Scientific and

Ethical committee of the Ahmadu Bello University

Teaching Hospital Zaria was obtained before the com-

mencement of the study. Informed consent of each of

the children’s parents or caregivers was obtained before

recruitment into the study.

Subjects and methods

Children between the ages of zero and fifty-nine months

admitted to the paediatric wards of the Ahmadu Bello

University Teaching Hospital (ABUTH) Zaria with diar-

rhoea or who developed diarrhoea while on admission in

the course of their hospital stay were consecutively re-

cruited between July 2008 and June 2009. For the pur-

pose of this study, diarrhoea was taken to be an increase

Results

A total of one hundred and eighty five children (185)

with diarrhoea aged 0 to 59 months, who consented for

the study were enrolled and all completed the study. The

prevalence of Cryptosporidium oocysts excretion among

the 185 under five children who had diarrhoea studied

was 17.8%. (Figure 1).

1

9

in frequency and fluidity of the stool of the patient.

Children whose parents or caregivers declined consent

for the study were excluded. Relevant demographic de-

tails of all children enrolled for the study were obtained

and recorded into a specifically designed proforma.

Fig 1: Prevalence of Cryptosporidium among the studied chil-

dren with diarrhoea

Stool sample was collected in dry clean container on the

day of recruitment from each study subject. This was

transported on the same day to the microbiology labora-

tory of ABUTH within 30 minutes of collection for mi-

crobiologic evaluation. To maximize recovery of oo-

cysts, stool samples were concentrated prior to micro-

scopic examination using the formalin-ethyl acetate

sedimentation stool concentration method for clinical

2

0

laboratories . A smear was made from the stool sedi-

ment on a clean slide, air dried and fixed with methanol,

Staining was with unheated carbolfuchsin and counter-

stained with 0.4% methylene blue. The smear was then

carefully examined microscopically for Cryptosporidiu-

Among the children studied, the gender distribution re-

flected a slight preponderance of females with a male to

female ratio of 0.73:1. The mean age of the children was

2

0

moocysts . An experienced parasitologist rechecked the

smears to ensure quality control.

1

studied children were 9.1kg ± 2.4 and 73.3cm ± 11.5

respectively. Those admitted with diarrhoea constituted

9.8 ± 6.0 months. The mean weight and length of the

Data obtained from the study was analyzed using the

computer SPSS version 15.0. Results are presented in

figures, tables and graphs as appropriate. Student’s t-test

was used to compare the means of normally distributed

continuous variable while differences between propor-

tions were evaluated by the Chi-square test and Yate’s

correction was applied as appropriate. A p-value of less

than 0.05 was considered to be statistically significant in

comparative analyses.

8

3.8% of the total while the rest developed diarrhoea in

the course of their hospital stay. There was no statisti-

cally significant difference in gender between those ad-

mitted with diarrhoea and those who developed diar-

rhoea in the course of their hospital stay.

Majority of the children (55.7%), as shown in Table 1,

were toddlers aged between 13 and 36 months. Sixty

three children (30.8 %) were infants, while nineteen

Case Management of children: All children recruited

for the study were routinely additionally investigated as

appropriate based on their other presenting symptoms

and signs to establish the existence or otherwise of con-

comitant disease according to the standard of care in the

hospital. All the children recruited for the study were

then managed accordingly in the Diarrhoeal Therapy

Unit (DTU) for diarrhoeal disease or in any of the paedi-

atric units when there was a concomitant disease. The

mothers and caregivers were taught the basic principles

of personal and environmental hygiene, home manage-

ment of diarrhoeal disease including prevention and

correction of dehydration using ORS, and maintenance

(

10.3%) were aged above thirty six months. Table 1

also shows that male children predominated beyond the

age of thirty six months. The age difference between

gender was not statistically significant (c = 2.768, df =

2

, p = 0.251).

Age prevalence

Table 2 shows the frequency distribution of Crypto-

sporidium infection in diarrhoeal stools of children stud-

ied by age category. The highest Cryptosporidium

prevalence rate (9.75%) was observed in toddlers

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Discussion

While cryptosporidiosis appears to be present in this

community all year round, prevalence was found to

increaseduring the rainyseason(69.7%). This clear

seasonal variation in the rate of Cryptosporidium oocyst

This study has revealed the presence of Cryptosporidiu-

moocyts in the stools of children aged less than five

years with diarrhoea in ABUTH. The 17.8% prevalence

of Cryptosporidium infection in the study population

may indicate that the organism is a significant pathogen

in children less than five years with diarrhoea in this

environment. This prevalence is within the observed

range of up to a quarter of all diarrhoeal illness in the

developing world in paediatric population being associ-

2

excretion in this study was of statistical significance(c =

4.509, p = 0.0337). The same seasonal variationhas als₁o₄

9

been observed in other studies from Uganda, Enugu

1

and the USA . Seasonal variation observed in this study

might be related to increased agricultural activities dur-

ing rainy season in our community that promote contact

with animals and their wastes used for agricultural

activities. This affects the number of oocysts in the

environment and promotes exposure to oocysts.

Furthermore, factors such as humidity and temperature

during the rainy season may enhance oocysts survival in

that season.

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ated with cryptosporidi₁o₆sis and similar to prevalence

rates of 14% in Ilorin, but much lower than 29% re-

1

4

ported among school children in Enugu . The rate of

detection of Cryptosporidium in this study was higher

than the reported rates of 12.5% in Enugu, 10.8% in

13

1

5

Port Harcourt and much_,h₈igher than 6.0% and 7.7%

6

reported in Guinea-Bissau and 8.1% reported in under

This study shows that the important clinical features

associated with Cryptosporidiosis are persistent diar-

rhea, watery stools, history of diarrheal illness in the

past year, stool frequency more than four times a day

and dehydration. This substantiates the literature where

it has been said that symptomatic cryptosporidium infec-

tion is char_,₉acterised by watery stools, persistent

11

five children in Addis₈Ababa as well as rate reported

1

-

in south west Nigeria.

The reasons for these differences are possibly due to

different methods used for detection of cryptosporidiosis

and differences in the study population. While several

community-based studies report lower prevalence rates

of cryptosporidiosis in children w₆_,i₁t₁h diarrhea in the

5

diarrhoea and a tendency to reoccur.

range between 6.0% and 8.1%

prevalence rates

reported among childre₁₆n recruited from hospitals tended

to be generally higher.

Conclusion

Although children aged 13 to 36 months were found to

shed oocyts most in the study, however there was no

statistically significant difference between the various

This study has clearly demonstrated the presence of

Cryptosporidium as an important pathogen among un-

der-five children presenting to ABUTH with diarrhoea.

It has also been able to identify some children more

likely to excrete Cryptosporidium oocysts in diarrhoeal

stools. Based on these findings, it is recommended that

evaluation of cases of diarrhoeal illnesses in children

less than five years presenting to the hospital should

include screening for Cryptosporidium oocysts, espe-

cially in children beyond the neonatal age.

Prevention of Cryptosporidium infections is by avoid-

ance of contamination of food and water sources by oo-

cysts through protection of water sources. Implementa-

tion of multiple barriers to safeguard public drinking

water sources can prevent cryptosporidiosis. However,

effective control of diarrhoea caused by cryptosporidium

remains largely elus₁i₀ve in sub-Saharan Africa and other

developing regions.

2

age groups in oocysts excretion. (c = 1.464, df = 2, p =

0

.481). The peak age of oocysts shedding in this study

was 22 months. This is in contrast to studies that found

9

that Cryptosporidium infectionpeaks at 10 months. This

study however agrees with other studies that showed

1

3

that young children less than 15 years, and in particular

1

5

children 0-2 years of age appear to be more susceptible

to Cryptosporidium. In this study, it appears that oocysts

excretion in stools appear to taper off as the children

approach sixty months. Similar finding was reported in a

study that showed that oocysts excretion subsided after

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3

four years.

6 months₅a_-₁n₆d were not encountered after the age of

1

Perhaps, a plausible reason for the later peak in age of

infection in this study is the possibility that age 22

months coincides with the age at cessation of breast

milk and a complete transition to family diet in this

community. It is also the age about which most children

begin to freely explore their environment, coming in

contact with animal dropings, contaminated foodand

objects that they readily put in the mouths.

Boys in this study were as affected as girls, with no sta-

tistically significant difference in their rates of crypto-

sporidium oocyst excretion in stools. This is in line with

other studies reflecting equal exposure and susceptibility

in the environment.

Authors’ contribution

Musa, S: Concept and design of study, data collection,

analysis and interpretation, writing of the initial draft.

Yakubu AM: Critical review for important intellectual

input to draft, final approval of the manuscript.

Olayinka AT: Design of laboratory method, contribution

of intellectual input to draft, approval of manuscript.

Conflict of interest: None

Funding: None

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between the 13 to 36 months age bracket. Only three

(1.6%) of the children aged more than 36 months had

Types of diarrhoea

Cryptosporidium Oocyts in their stools. However, these

The type of diarrhoea seen among the studied population

shows that acute watery diarrhoea occured in 132 (71%)

of all children presenting with diarrhoea, while persis-

tent diarrhoea and acute bloody diarrhoea were seen in

differences, when subjected to statistical analyses, were

2

found not to be significant.

0.481).

(c = 1.464, df = 2, p =

3

9 (21%) and 14 (8%) of the children, respectively.

Table 1: Characteristics of children with diarrhoea studied for

Cryptosporidium oocysts in stools at ABUTH, Zaria.

Clinical correlates of cryptosporidium oocysts excretion

It was found out that oocysts excretion was more likely

in children with persistent diarrhoeal illness (p = 0.0001,

Fisher’s exact test), watery stools (p = 0.0002, Fisher’s

exact test), previous history of diarrhoeal illness in the

past year (p = 0.0005, Fisher’s exact test), high

frequency stools (p = 0.0001, Fisher’s exact test) and

dehydration (p = 0.0065, Fisher’s exact test) as shown in

Table 4.

Characteristic

Frequency (%)

Gender

Male

78 (42.2)

Female

107 (57.8)

Period of development of diarrhoea*

Admitted with Diarrhoea

Males

Females

Developed diarrhoea on admission

Males

Females

155 (83.8)

65 (41.9)

90 (58.1)

30 (16.2)

13 (43.3)

17 (56.7)

Table 4: Clinical correlates of cryptosporidium oocysts in

children studied

p value,

Fisher’s

exact test

Logistic

Regression

Analysis

OR (95%

CI)

(

diarrhoea and those who developed diarrhoea in the course of

their hospital stay, c = 0.020, df = 1, p = 0.887)

No difference in gender between those admitted with

Variable

Cryptosporidium Oocyts

2

Positive

Negative

Table 2: Distribution of Cryptosporidium infection by age