Human Campylobacteriosis in Developing Countries

1 Emerging Infectious Diseases Vol. 8, No. 3, March 2002237 SYNOPSISH uman Campylobacteriosis in Developing Countries1 Akitoye O. Coker,* Raphael D. Isokpehi,* Bolaji N. Thomas,* Kehinde O. Amisu,* and C. Larry Obi Campylobacteriosis is a collective description for infectious diseases caused by members of the bacterialgenus Campylobacter. The only form of Campylobacteriosis of major public health importance is Campylo-bacter enteritis due to C. jejuni and C. coli. Research and control efforts on the disease have been con-ducted more often in developed Countries than Developing Countries . However, because of the increasingincidence, expanding spectrum of infections, potential of HIV-related deaths due to Campylobacter, andthe availability of the complete genome sequence of C.

2 Jejuni NCTC 11168, interest in campylobacteriosisresearch and control in Developing Countries is growing. We present the distinguishing epidemiologic andclinical features of Campylobacter enteritis in Developing Countries relative to developed surveillance programs and international collaborations are needed to address the substantialgaps in the knowledge about the epidemiology of Campylobacteriosis in Developing Countries . ampylobacteriosis is a collective description for infec-tious diseases caused by members of the bacterial genusCampylobacter. The only form of Campylobacteriosis of majorpublic health importance is Campylobacter enteritis due toC.

3 Jejuni and C. coli (1). The rate of Campylobacter infectionsworldwide has been increasing, with the number of cases oftenexceeding those of salmonellosis and shigellosis (2). Thisincrease, as well as the expanding spectrum of diseases causedby the organisms, necessitates a clearer understanding of theepidemiology and control of and control of diseases of public healthimportance in Developing Countries have focused on diseasessuch as malaria, tuberculosis, trypanosomiasis, onchocerciasis,and schistosomiasis (3). Programs for diarrhea and acute respi-ratory illness also exist (4). These programs have extensivesupport from the World Health Organization (WHO).

4 Campylobacter is one of the most frequently isolated bac-teria from stools of infants with diarrhea in Developing coun-tries a result of contaminated food or water (5,6). However,national surveillance programs for Campylobacteriosis gener-ally do not exist in most Developing Countries despite the sub-stantial burden of disease. Most data available oncampylobacteriosis in Developing Countries were collected as aresult of support provided by WHO to many laboratories indeveloping Countries , including grants for epidemiologic stud-ies and Lior serotyping antisera provided by the Public HealthService of Canada (5,7). The number of reviews and updateson Human Campylobacteriosis in developed Countries (8-11) isgreater than that for Developing Countries (5,6).

5 This disparitymay be because Campylobacter-associated diarrhea in devel-oping Countries is not pathogenic in patients >6 months of , a community-based longitudinal study provided evi-dence that infection could be pathogenic beyond the first 6months of life in Developing Countries (12). Furthermore, thesequencing and publication of the complete genome ofC. jejuni NCTC 11168 have heralded a renaissance of interestin this organism, offering researchers worldwide, including indeveloping Countries , novel ways to contribute to the under-standing the organism s biology (13). Thus, to promoteresearch and control of Campylobacteriosis in developingcountries, review information on Human Campylobacteriosis inthese Countries is urgently needed.

6 We present the distinguish-ing features of Campylobacteriosis in Developing Countries rel-ative to developed , Developing Countries do not have national sur-veillance programs for Campylobacteriosis ; therefore, inci-dence values in terms of number of cases for a population donot exist. Availability of national surveillance programs indeveloped Countries has facilitated monitoring of sporadiccases as well as outbreaks of Human Campylobacteriosis (2,8-11). Most estimates of incidence in Developing Countries arefrom laboratory-based surveillance of pathogens responsiblefor diarrhea. Campylobacter isolation rates in developingcountries range from 5 to 20% (6).

7 Table 1 shows isolationrates for some Countries according to WHO regions from stud-ies of diarrhea in children <5 years old (14-25). Despite thelack of incidence data from national surveys, case-controlcommunity-based studies have provided estimates of 40,000 to60,000/100,000 for children <5 years of age (6,12). In con-trast, the figure for developed Countries is 300/100,000 (8).Estimates in the general population in Developing and devel-oped Countries are similar, approximately 90/100,000 (5,6,8),confirming the observation that Campylobacteriosis is often a1 Portions of this review were presented at the World Health Organiza-tion Consultation on the Increasing Incidence of Campylobacteriosis inHumans, Copenhagen, Denmark, November 1-25, 2000.

8 In addition,relevant emerging information from the 11th International Workshop onCampylobacter, Helicobacter and Related Organisms, held in Freiburg,Germany, September 1-5, 2001, are included.*University of Lagos, Idi-Araba, Lagos, Nigeria; and University ofVenda for Science and Technology, Thohoyandon, South AfricaCSYNOPSIS238 Emerging Infectious Diseases Vol. 8, No. 3, March 2002pediatric disease in Developing Countries . The isolation andincidence rates in some Developing Countries have increasedsince their initial reports (17). This increase has often beenattributed to improved diagnostic methods, but an actualincrease in incidence was observed in Campylobacter-associ-ated diarrhea in the caribbean island of Cura ao (26).

9 Age of InfectionIn Developing Countries , Campylobacter is the most com-monly isolated bacterial pathogen from <2-year-old childrenwith diarrhea (Table 2). The disease does not appear to beimportant in adults. In contrast, infection occurs in adults andchildren in developed Countries . Poor hygiene and sanitationand the close proximity to animals in Developing Countries allcontribute to easy and frequent acquisition of any entericpathogen, including Campylobacter. Although infections ininfants appear to decline with age (Table 2), a comprehensivecommunity-based cohort study in Egypt has shown that infec-tion could be pathogenic regardless of the age of the child,underscoring the need for strengthening prevention and con-trol strategies for Campylobacteriosis (12).

10 Polymicrobial Infections Involving CampylobacterCampylobacter is isolated relatively frequently withanother enteric pathogen in patients with diarrhea in develop-ing Countries . In some cases half or more patients withCampylobacter enteritis also had other enteric pathogens(23,30). Organisms reported include Escherichia coli, Salmo-nella, Shigella, Giardia lamblia, and Rotavirus. Polymicrobialinfections involving Campylobacter are rare in developed coun-tries (5,6).Isolation of Campylobacter in Healthy ChildrenThe recovery of Campylobacter organisms from childrenwithout diarrhea is common in Developing Countries . In somereports the isolation rates for symptomatic and asymptomaticchildren were not statistically significant.