Parents who move to the tropics with their children often worry about tropical diseases. Most of the data available on screening children returning home from living in the tropics are from 1952-63 from American children.1 More recent findings in asymptomatic people returning to the United Kingdom have been reported.2 We aimed to determine whether it is worthwhile to routinely screen children without symptoms returning home from the tropics.
Subjects, methods, and results
During 1987-95 all children visiting our hospital for a medical check up after a stay in the tropics were studied. This check up was obligatory under their parents’ terms of employment. Our protocol included a questionnaire (completed by the parents), physical examination of the child, and additional investigations. These investigations included a full blood cell count; eosinophil count; liver function tests; urea and creatinine concentrations; hepatitis A and B serology; thick smear; schistosoma and filaria serology (if the child had stayed in endemic areas); urine analysis; stool culture; analysis of three stool samples for ova and cysts; tuberculin skin test; and a chest x ray if indicated. The same specialist (JJMT) performed all consultations. Data were analysed with EpiInfo version 5.0.
Results
A total of 216 children (103 girls) were seen during 282 check ups (some children had lived in the tropics more than once) (table). In 175 (62%) cases (check ups), children had lived in sub-Saharan Africa. Ninety three children (43%) were born in the tropics. The length of stay overseas ranged from 3 months to 13 years; in 150 (53%) cases the stay was 1-3 years. Age at first check up ranged from 3 months to 16 years (mean 4.75, median 3.6). In 29 (10%) cases children were seen early, mainly because they had one or more complaints: abdominal pain (13 children), diarrhoea (9), or fever (8). These cases were classed as symptomatic. In the 253 asymptomatic cases of disease—that is, among children seen at their scheduled appointment—parents reported that 40 had abdominal pain and 31 had diarrhoea. On physical examination, few abnormalities associated with tropical diseases were detected in children with symptoms: hepatosplenomegaly (in three children) and cutaneous larva migrans (one child).
Most conditions were diagnosed by laboratory investigation. Twelve of 58 (21%) asymptomatic cases of giardiasis were associated with abdominal complaints. Results of tuberculin skin tests were available for 187 children, of whom 149 had been vaccinated with BCG. In 47 (25%), induration was less than 10 mm, and two children had indurations of 12 mm and 15 mm with normal physical findings and normal chest x rays. A total of 112 (75%) of the children vaccinated with BCG did not respond to the tuberculin test. Tropical diseases were diagnosed in 99/253 (39%) asymptomatic and 15/29 (52%) symptomatic cases. All children with parasitic infections received appropriate treatment as outpatients. Only one child needed admission; this was for treatment of relapsing fever.
Comment
These findings can be considered representative for all children returning home, especially those returning from sub-Saharan Africa. Children should be seen early if they have any symptoms but children without apparent symptoms also may have abdominal complaints. We found a higher incidence of tropical diseases in asymptomatic children than Carroll et al2 (39% v 25%), probably because of our higher incidence of giardiasis (23% v 4%). Most cases of giardiasis in our study were asymptomatic. The incidence of unexplained eosinophilia in 24 (10%) of 253 asymptomatic cases is similar to that found by others.2–4 A lack of response to tuberculin skin testing among 75% of the children who had been vaccinated with BCG could be explained by inadequate testing technique, failure of the vaccination to produce tuberculin sensitivity, or diminishing sensitivity occurring over time.5
Routine screening of children without symptoms returning home after living in the tropics is worth while. Laboratory testing will identify most cases of tropical disease. Screening can be carried out by well informed general practitioners using a standard protocol.
Table.
Number (percentage) of diagnoses of tropical disease found during 282 check ups in 216 children in the Netherlands, 1987-1995
| Diagnosis | Cases
|
||
|---|---|---|---|
| Asymptomatic disease (n=253) | Symptomatic disease (n=29) | Total (n=282) | |
| Giardiasis | 58 (23) | 3 (10) | 61 (22) |
| Unexplained eosinophilia | 24 (10) | 3 (10) | 27 (10) |
| Schistosomiasis | 19 (8) | 2 (7) | 21 (7)* |
| Trichuriasis | 7 (3) | 2 (7) | 9 (3) |
| Ascariasis | 5 (2) | 1 (3) | 6 (2) |
| Hepatitis A infection | 4 (2) | 2 (7) | 6 (2)† |
| Campylobacter jejuni infection | 3 (1) | 2 (7) | 5 (2) |
| Entamoeba histolytica or Entamoeba dispar infection | 3 (1) | 2 (7) | 5 (2) |
| Ancyclostomiasis | 4 (2) | — | 4 (1) |
| Filariasis | 2 (0.8) | 1 (3) | 3 (1)‡ |
| Relapsing fever | — | 1 (3) | 1 (0.4) |
| Hepatitis B infection | 1 (0.4) | — | 1 (0.4) |
| Malaria | — | 1 (3) | 1 (0.4) |
| Other | 2 (0.8)¶ | 4 (14)§ | 6 (2) |
| Total diagnoses | 132 | 24 | 156 |
| No of cases with one or more diagnosis | 99 (39) | 15 (52) | 114 (40) |
All positive on serological testing and three children also positive for ova.
All tested positive for anti-hepatitis A IgM.
All positive on serological testing and one child also positive on thick smear.
One case of strongyloidiasis and one case of salmonellosis.
One case each of borreliosis, rickettsiosis, larva migrans, relapsing fever.
Acknowledgments
We thank the nursing and administrative staff of the paediatric clinic for their contribution in carrying out the protocol.
Footnotes
Competing interests: None declared.
References
- 1.Carter JP, Frame JD. Medical problems of American children living overseas. Pediatr Clin North Am. 1970;17:255–272. doi: 10.1016/s0031-3955(16)32408-7. [DOI] [PubMed] [Google Scholar]
- 2.Carroll B, Dow C, Snashall D, Marshall T, Chiodini PL. Post-tropical screening: how useful is it? BMJ. 1993;307:541. doi: 10.1136/bmj.307.6903.541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Weller PF. Eosinophilia in travellers. Med Clin North Am. 1992;76:1413–1432. doi: 10.1016/s0025-7125(16)30294-2. [DOI] [PubMed] [Google Scholar]
- 4.Isaacson M, Frean JA. Diagnostic and management approaches in returning travellers. In: DuPont HL, Steffen R, editors. Textbook of travel medicine and health. Hamilton, Ontario: BC Decker; 1997. [Google Scholar]
- 5.Committee on Infectious Diseases; American Academy of Pediatrics. 1997 red book: report of the Committee on Infectious Diseases. 24th ed. Elk Grove Village, IL: American Academy of Pediatrics; 1997. [Google Scholar]