Household Hygiene Variables and Its Impact on the Risk of Campylobacter Diarrhea among Children of Rural Egyptian Villages

K. Hassan1, A. Mansour1, A. Hafez2, H. I. Shaheen1, S. El Alkamy2, M.S. Riddle4, J. W. Sanders3, A.W. Armstrong4, and N. El Sayed2

1 US Naval Medical Research Unit No. 3, Cairo, Egypt, 2 Ministry of Health and Population, Cairo, Egypt, 3 US Naval Medical Research Center Detachment, Lima, Peru, 4 US Naval Medical Research Center, Washington D.C., USA

Abstract:Background: Campylobacter sp. is one of the most frequently isolated bacteria from stools

of infants with diarrhea in developing countries. Among other factors including the host and agent, environmental factors including domestic sanitation and poor hygienic conditions are thought to influence risk of Campylobacteriosis in these endemic settings. The present study aims to identify the impact of various hygiene variables on increased risk of Campylobacter associated diarrhea among children <2 years of age in rural Egyptian villages.

Methods: A prospective birth cohort study of 348 infants was conducted from January 2004 to April 2007 in five villages of the Nile Delta region. Neonates were enrolled at birth and followed up to 24 months of age. Children were visited twice a week to survey for acute diarrhea. A detailed observational household hygiene survey was completed in-house approximately every six months during the two-year follow-up period. The hygiene questionnaire consisted of ten questions and covered the domestic environmental conditions of the home and hygiene characteristics of sleeping room, eating room, cooking room, garbage containers, previously prepared food, washing facilities, bathroom and bathing facilities, water sources and containers, and flies in the house. Adjusted Incidence Rate Ratios (IRR) of hygiene variables were calculated for the primary outcome of Campylobacter-specific diarrhea illness rates.

Results: The risk of Campylobacter associated diarrhea significantly increased with several household hygiene variables. Presence of human or animal feces around the bathroom (IRR 2.48, p<0.001), non-daily washing of garbage containers (IRR 1.93, p<0.05), location of the bathroom inside the house (IRR 2.39, p<0.05), absence of barriers to keep birds and animals out eating rooms (IRR 1.51, p<0.05), and cooking rooms (IRR 1.70, p<0.05), and drain of latrine open to the environment (IRR 1.53, p<0.05) all increased a child’s risk of Campylobacter-diarrhea in the household.

Conclusion: Factors related to household hygiene and construction appear to be associated with an increased risk of Campylobacter-associated diarrhea. Further study is warranted to evaluate these factors on all-cause and other pathogen-specific causes of diarrhea. These data are important in highlighting some potentially modifiable factors which could reduce the burden of disease in resource-poor settings.

Introduction:

Campylobacter enteritis due to C. jejuni and C. coli are the major forms of Campylobacteriosis of public health importance. Incidence of Campylobacter has gradually increased over the last decade. It is reported now among the leading cause of bacterial gastroenteritis. Campylobacter infections represent a considerable burden on economic and public health resources. The epidemiology of Campylobacter diarrhea appears to differ between developed and developing countries. In the developed world, both children and adults are at risk for Campylobacter infection, while in the developing world Campylobacter is endemic, and infection is usually limited to children. In the developed world, the transmission of the organism has been associated with the consumption of unpasteurized milk, undercooked meats, contaminated water, and travel to Campylobacter endemic areas. In the developing world, poor household hygiene and maternal hygiene behaviors relating to child-care practices are often linked to childhood diarrheal illness.

Case-control community-based studies have provided estimates of Campylobacter infections in developing world ranging between of 40,000 to 60,000 per 100,000 children less than five years of age. In contrast, the figure for developed countries is 300 per 100,000.

  Materials and Methods:

A prospective birth cohort study of 348 infants was conducted from January 2004 to April 2007 in five villages located in Abu Homos, a rural district located in the Nile Delta region in northern Egypt. Eligible births were identified from a census of 1,916 households representing a total population of 15,675 people. Neonates were enrolled at birth and followed up to 24 months of age. Written informed consent was obtained from the mother and from the parent of the eligible child. Children were visited twice a week to survey for acute diarrhea. If any loose or liquid stools were reported, a fecal specimen and two rectal swabs were collected. From each specimen, conventional microbiological procedures were used to isolate and identify Campylobacter as well as other pathogens.

In addition, a detailed observational household hygiene survey was completed in-house approximately every six months during the two-year follow-up period. The hygiene questionnaire consisted of ten sections and covered the domestic environmental conditions of the home and hygiene characteristics of sleeping room, eating room, cooking room, garbage containers, previously prepared food, washing facilities, bathroom and bathing facilities, water sources and containers, and presence of flies in the house.

A "diarrheal day" was defined as the occurrence of ≥3 non-formed stools (or > 1 if bloody) in a 24-h period. In addition, if the child was breast-fed and the stool was not bloody, the mother had to report an increase in frequency or a reduction in consistency of the stools, compared with what she considered to be normal.

A “diarrheal episode” was defined to begin on the first day of loose or liquid stools after at least three consecutive non diarrheal days and ending on the last diarrheal day to be followed by at least three consecutive non diarrheal days. An episode of diarrhea was classified as Campylobacter diarrhea, if Campylobacter was isolated at any time in the entire duration of the episode.

From the twice-weekly surveillance data, incidence rates of Campylobacter diarrhea episodes were calculated. Data of diarrhea episodes were linked to the prior household hygiene survey. The household hygiene survey information was assumed to be time invariant for the interval between two surveys. Bi-variant analysis was utilized to assess the association between Campylobacter diarrhea and each hygiene variable. Crude relative rate was computed as a ratio of the incidence rates in the presence and absence of each household hygiene variable under consideration. Significant crude relative rates were adjusted for child’s age in years, season of diarrhea

Disclaimer:

Authors’ Disclaimer Statement: The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government. Work was funded by work unit # 6000.RAD1.D.E0301.

 Human Use Statement: The study protocol # 145 was approved by the Naval Medical Research

Unit No. 3 Institutional Review Board in compliance with all applicable Federal regulations governing the protection of human subjects.

 Copyright Assignment statement: I am a military service member (or employee of the U.S.

Government). This work was prepared as part of my official duties. Title 17 U.S.C. §105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. §101 defines a U.S. Government work as a work prepared by a military service member or employee of the U.S. Government as part of that person’s official duties.

Incidence rate (IR), crude and adjusted relative risk (IRR) of sole Campylobacter diarrhea by hygiene variables,Natural Immunity Study, 2004 - 2007, Abu Homos, Egypt.

occurrence (warm/cold), child’s breastfeeding status, crowding (number of persons per sleeping room, ≥ 3.5 persons as high or moderate crowding and <3.5 persons as low crowding), and for the correlation between repeated observations of the same child. All statistical analyses were performed using SAS software (version 9.1).

Results:

Of the 348 newborns enrolled in the study, 285 completed two years of follow-up. Mean duration of follow up period was 20.3 months. 4001 episodes of diarrhea were detected over the study period, resulting in an incidence of 8.18 episodes of diarrhea per child/year. The diarrheal attack rates were observed to decline over the age of child. Diarrhea incidence rate during the first year of life was 10.0 episodes per child/year as compared with 6.4 episodes per child/year during the second year of life. Enterotoxigenic E. coli was the most common pathogen isolated (756 episodes) with an incidence of 1.5 episodes per child/year followed by Campylobacter (319 episodes) with an incidence of 0.63 episodes per child/year. Campylobacter incidence rate was three times higher during the first year of age when compared to that during the second year of age (1.0 and 0.3 respectively). The incidence rate of Campylobacter diarrhea during the warm months was twice the rate as compared with the cold months (0.8 and 0.4 respectively). Out of 319 Campylobacter diarrhea episodes, 75% were found to be sole pathogen. Enterotoxigenic E. Coli was isolated as copathogen in 57 (18%) of Campylobacter diarrhea episodes, followed by Rotavirus in 10 episodes (3%); Salmonella, Shigella, or other mixed infections were isolated in the remaining 4% of Campylobacter diarrhea episodes. Speciation performed on the 319 Campylobacter diarrhea episodes indicate that 235 (74%) were C. jejuni, 78 (24%) were C. coli, and 6 (2%) were mixed infections (C. jejuni and C. coli). No significant difference in the distribution of Campylobacter species by season was observed. A total of 280 (87.8%) of Campylobacter diarrhea episodes were identified as acute episodes (episode’s length < 14 days and no blood in stool was observed), 16 (5.0%) as dysentery (episode’s length < 14 days and blood in stool was observed), and 23 (7.2%) as persistent (episode’s length > 14 days).

For studying the impact of household hygiene variables on the risk of Campylobacter diarrhea, Campylobacter diarrhea episodes occurred before the collection of first household hygiene information were excluded (n=39). In addition children with no household hygiene information were also excluded (n=33). 201 episodes out of 240 of sole Campylobacter diarrhea episodes were included in the analysis.

The relative risk of Campylobacter diarrhea significantly increased with several household hygiene variables. The analysis showed that:

•Presence of human or animal feces around the bathroom was the highest significant household hygiene factor associated with the increasing relative risk of Campylobacter diarrhea episodes (IRR 2.48, p<0.001).

*: Adjusted for child’s age in years, season of diarrhea occurrence, child’s breastfeeding status, crowding (number of persons per sleeping room, >= 3.5 person as high or moderate crowding versus <3.5 person as low crowding), and for the repeated subject of the same child, using Logistic Regression Model and SAS Software.(1): includes sewage system, sealed pit, unsealed pit, and non-governmental drain net. §: P <0.05 ¶: P <0.001

•Pluming factors (location of the bathroom, and latrine drain type) were significantly associated with the increasing relative risk of Campylobacter diarrhea episodes. Open latrine drain to environment had a significant impact in increasing relative risk of Campylobacter diarrhea episodes (IRR 1.53, p<0.05) versus other types of drains (such as sewage system, sealed or unsealed pit and non-governmental drain net). Location of the bathroom inside the house was significantly found to increase the relative risk of disease (IRR 2.39, p<0.05).

•Absence of barriers to keep birds and animals out eating rooms, and cooking rooms increases a child’s risk of Campylobacter diarrhea in the household (IRR 1.51, p<0.05 and IRR 1.70, p<0.05 respectively).

•Non-daily washing of garbage containers increased a child’s risk of Campylobacter diarrhea (IRR 1.93, p<0.05). Conclusion:

Factors related to household hygiene and construction appears to be associated with an increased risk of Campylobacter diarrhea disease. Further study is warranted to evaluate these factors on all-cause and other pathogen-specific causes of diarrhea. These data are important in highlighting modifiable factors which could reduce the burden of disease in resource-poor settings. The incidence of Campylobacter diarrhea identified in this study, and its associated public health and economic burden, emphasize the importance of the need for a safe and effective vaccine that can confer protection in early infancy.

Presentation No. 2915, Authors contact: khaled.hassan.eg@med.navy.mil

Hygiene variables Code IR Crude IRR Adjusted IRR*Barrier to keep birds and animals out of eating room No

Yes0.55 (1/1.8)0.48 (200/419.1)

1.50 (0.98, 2.27) 1.00

1.51 (1.00, 2.27) §1.00

Barrier to keep birds and animals out of cooking room NoYes

0.52 (130/250.1)0.42 (71/170.8)

1.73 (1.15, 2.59) §1.00

1.70 (1.15, 2.51) §1.00

Washing of garbage containers Not dailyDaily

0.76 (34/ 44.7)0.44 (167/376.2)

1.96 (1.25, 3.05) §1.00

1.93 (1.27, 2.92) §1.00

Fixed raised bowl or basin in washing facility NoYes

0.61 (67/109.8)0.43 (134/311.1)

1.72 (1.09, 2.74) §1.00

1.48 (1.01, 2.18) §1.00

Location of the bathroom Inside the houseOutside the house

0.49 (195/399.4)0.28 (6/21.5)

2.19 (1.01, 4.78) §1.00

2.39 (1.06, 5.38) §1.00

Latrine drain To open environmentTo others (1)

0.52 (104/199.0)0.44 (97/221.9)

1.41 (0.95, 2.10)1.00

1.53 (1.06, 2.20) §1.00

Feces on bathroom floor YesNo

1.58 (6/3.8)0.47 (195/417.1)

2.61 (1.10, 6.19) §1.00

1.84 (1.02, 3.33) §1.00

Human or animal feces within 3 paces of the outside wall of the bathroom

YesNo

1.74 (8/4.6)0.46 (193/416.3)

3.29 (1.90, 5.69) ¶1.00

2.48 (1.56, 3.95) ¶1.00

Functioning tap in the compound is the home water source NoYes

0.71 (52/73.4)0.43 (149/347.5)

2.01 (1.24, 3.23) §1.00

1.57 (1.04, 2.37) §1.00

Drinking water source is tap in compound NoYes

0.41 (132/321.6)0.69 (69/99.3)

1.93 (1.23, 3.04) §1.00

1.40 (0.94, 2.08)1.00

Cooking water source is tap in compound NoYes

0.41 (132/321.7)0.70 (69/99.2)

1.95 (1.25, 3.07) §1.00

1.40 (0.94, 2.08)1.00