TYPHOID CARRIERS AMONG CHILDREN IN SOHAG
Najah M AbdelRaheem, Gihan Y Yousef, Hatem M Shalaby, Mohammed Eltorky Ahmed AbdelAzziz
Public health department, Pediatric Department, Department of Microbiology. Sohag University.
Address for Correspondence
Dr Gihan Y Yousef, Sohag university, Sohag faculty of medicine, Sohag, Egypt.
Email
jhakeem11@yahoo.com
Abstract
Objectives: Enteric fever due to Salmonella typhi is a major public health problem. In endemic areas, children aged 1-5 years are at the highest risk of infection. Between 1% and 5% of patients with acute typhoid infection have been reported to become chronic carriers, depending on age, sex and treatment regimen. In this study we study the prevalence of chronic typhoid carriers among children in Sohag.

Patients and method: Five hundred children between 2-14 years (421 male and 79 female) attending out patients paediatrics- clinic were examined for the existence of typhoid bacilli in their urine and stool.

Results: Typhoid bacilli were found in 18.7% as stool carriers and 3.1% as urinary carriers. Only 34.7% of the stool carrier has definite history of typhoid and 12.3% in the urinary carrier. Highest percentage of carriers was above 12 years of age (40.2%). Chronic stool and urinary carriers were more in rural than urban areas. Symptoms suggesting typhoid fever was present in 58.6% of stool carriers and 18.2% in urinary carriers.

In conclusion: Chronic typhoid carriers are present in considerable percentage in pediatric age group in Sohag.
Keywords
Typhoid, carriers, prevalence, children
Introduction
Enteric fever due to Salmonella Typhi is a major public health problem. Its real impact is difficult to estimate because the clinical picture is confused with those of many other febrile infections. It is estimated to have caused 21.6 million illnesses and 216,500 deaths globally in 2000, affecting all ages. (1) In endemic areas, children aged 1-5 years are at the highest risk of infection. (2) In young children, the clinical syndrome is often a non-specific febrile illness that is not recognized as typhoid fever. In more recent years, prospective studies have shown that, although the incidence of classic typhoid fever in patients is highest in adolescents and young adults, the overall incidence of blood culture-confirmed disease is generally highest in children aged 3-9 years and declines significantly in late adolescence. (3) After clinical recovery asymptomatic fecal excretion of salmonella typhi occurs for several months particularly in young children. Individuals that excrete salmonella typhi for more than three months after infection usually become chronic carriers. Between 1% and 5% of patients with acute typhoid infection have been reported to become chronic carriers, depending on age, sex and treatment regimen. The propensity to become a carrier follows the epidemiology of gall bladder disease, increasing with age and being greater in females than in males. The risk of becoming a chronic carrier is low in children and increases with age. (4) The incidence of biliary tract diseases is higher in chronic carrier. Although chronic urinary carrier may also occur, it is rare and found mainly in individuals with schistosomiasis. (5) This study aims to recognise the amplitude of typhoid carriers among children in Sohag and identify the epidemiologic aspects of the problem.
Methods & Materials
This study was done in Sohag university hospital in a period from September 2005 to December 2006. Five hundred children between 2-14 years (421 male and 79 female) attending out patients paediatrics- clinic were examined for the existence of typhoid bacilli in their urine and stool.

History taking included age, sex, residence, history of fever, weight loss, poor appetite, change of bowel habits, the source of water supply (an enquiry of whether families were using the general supply, water pump or tap water) availability of latrine at house, history of pervious attack of typhoid fever in the family, history suggesting of typhoid fever such as abdominal pain and prolonged pyrexia, or sure history of typhoid fever. Full physical examination was done to detect weight loss, fever, pallor, icterus or splenomegaly. Urine and stool sample were obtained for: Culture and sensitivity for detection of S. Typhi bacilli. Fresh urine and stool samples were cultured on Salmonella-Shigella agar (S&S) and incubated at 37°C for at least 7 days and then examined for detection of S.typhi colonies. Also biochemical reaction was done to differentiate between salmonella and shigella.

Statistics:
Data entry and statistical analysis was done using SPSS version 10. P value was considered significant when < 0.005. P value on Chi-square was done by using EP info program.
Results
Table (1): shows that out of 500 children, 91 (18.2%) child has typhoid bacilli in their urine or stool. Stool carrier represent 82.4% (75 children) while 17.6% (16 children) were urinary carrier. Inspite of higher prevalence at age group > 12 years (41.3% in stool carriers and 37.5% in urinary carriers) there is insignificance difference in carrier state between different age groups (p Value = 0.236). There were 57 males (62.6%) and 34 females (37.3%). Males had significantly higher carrier rates than females.

Table (1): Number, Type, Age, and Sex Distribution of Typhoid Carriers
Examined cases Stool carriers Urinary carriers Negative cases P value
NO. % NO. % NO. %
75 15% 16 3.2% 409 81.% 0.000 (HS)
Distribution by age:
2-6 yrs.
6-12 yrs.
>12 yrs.

21
23
31

28
30.6
41.3

4
6
6

25
37.5
37.5

223
92
94

54.5
22.4
22.9
0.236 (NS)
(2.88)

Distribution by
Sex: Male
Female

46
29

62.6
37.4

11
5

68.7
32.3

215
193

52.5
47.2
0.000 (HS)
(12.15)


NS: Non significant
HS: Highly significant
 P Value on Chi-square

Table (2): Shows the residence, water supply and presence of latrine in the house. 45 (40%) stool carriers lived in urban areas while 30 (60%) lived in rural areas. In the urinary carriers, 4 (25%) lived in the urban areas and 12 (75%) lived in rural areas. As regards to water supply, percentage of urinary and stool carriers were more in cases using water pump and general source of water supply than cases using tap water. Also as regards availability of latrine, about 74.6% of stool carriers and 56.2% of urinary carriers had latrine in their house.

Table (2) Distribution of residence, source of water supply and latrine availability in the studied group.
Examined cases Stool carriers Urinary carriers Negative cases P value
NO. % NO. % NO. %
0.000
(7.43)
75 15% 16 3.2% 409 81.8%
Distribution by residence:
Urban
Rural

30
45

40
60

4
12

25
75br>

96
313

23.4
76.5
Source of water supply:
Tap
Water pump
General source

22
26
27

29.3
34.6
36

4
4
6

25
37.5
37.5

377
23
9

92.1
5.6
2.2
0.000
(193.2)
Availability of latrine
Available
Not available

56
19

74.6
25.3

9
7

56.2
43.75

379
30

92.2
7.3
0.000
(33.6)


P value on Chi-square

Table (3): shows the family history of typhoid, where only 34.7% of the stool carriers has history of typhoid and 12.3% in the urinary carriers.

Table (3) Family History of Typhoid Fever of the Studied Group
Family history of typhoid Present Absent P Value
No. % No. %
Stool Carriers 26 34.6 49 65.3 0.000
(26.08  )
Urinary Carriers 2 12.5 14 87.5 0.001
(9.8  )


P value on Chi-square

Table (4) shows symptoms suggesting typhoid fever or biliary diseases and schistosomiasis.
Studied groups History of Stool carriers P Value Urinary carriers P value
No. % No. %
Fever 44 58.6 0.000 3 18.7 0.000
Anorexia 20 26.6 0.000 5 31.2 0.001
Abdominal pain 45 60 0.000 12 75 0.000
Jaundice 3 4 0.24 0 0  
Schistosomiasis 12 16 0.650 10 62.5 0.000
Pervious attack of typhoid fever 18 24 0.000 6 37.5 0.000


Discussion
This study showed that typhoid carriers are present in asymptomatic children in a rate of 18.2%. Alverz et al found this high rate of carriers among families of typhoid child and attributed this high rate of carriers to high environmental pollution. (6) Also in study done in food handlers in India by Senthilkumar et al it was found that 17.4% of the studied group were asymptomatic typhoid carriers. (7) Chin et al have stated that chronic carriers are the most important reservoirs for S.typhi. (8) About 2-5% of cases become chronic carriers, some after asymptomatic infection. Little is known about the percentage of chronic typhoid carriers in children.

In this study, stool carriers to urinary carriers is 6 to 1 ratio. Itah et al have stated that chronic fecal carriers outnumber urinary carriers by ten to one. (9) Urinary carriers found to be associated with infection with schistosomiasis. (5) This explains higher incidence of urinary carriers in this study due to higher incidence of schistosomiasis. Kamel et al mentioned that in Egypt, carrier state is associated with urinary pathology such as schistosomiasis and may be evidenced by urinary excretion. (10)

The highest percentage of carriers was at age above 12 years (40.2%). This is agreed in a study done by Cleary et al, who mentioned that the risk of becoming a chronic carrier is low in children and increases with age. (4) Traditionally the age range considered to be at greatest risk was 5-25 years. However this has been questioned in a study from a private laboratory in Bangladesh, which found that the 57% of S. typhi isolates were in children less than 5 years of age and 27% less than 2 years. (11)

This study showed that chronic stool and urinary carriers were more in rural than urban areas and this may be due to low hygiene in rural areas. In study done by Alverz et al about the relation of asymptomatic typhoid carriers in the family of typhoid child and the hygienic measures, they concluded that, the effective hygiene behaviours were observed in families who had a lower incidence of carriers and incorrect hygiene habits were associated with higher carrier rates including those of the child itself (p < 0.05), of the family in general, of those who prepare the food (p < 0.05) and of those linked to the fecal-oral cycle (p < 0.01). (6) Also this high percentage may be due to bad water supply and swage disposal in the rural areas than in the urban. This is supported by the high percentage of carriers located in families who have their water supply from water pump or general source and who have no latrine in the house. Al-Quarawi et al stated that as typhoid fever is transmitted through feco-oral route, so high rate has been attributed to the consumption of contaminated drinking water and foodstuffs. (12) The infection is transmitted by ingestion of food or water contaminated with faeces. The highest incidence occurs where water supplies serving large populations are contaminated with faeces. However Camilo et al, suggest that water-borne transmission of S. typhi usually involves small inocula, whereas food-borne transmission is associated with large inocula and high attack rates over short periods. (13)

This study showed that 74.6% of the stool carriers had a latrine in their homes. This is against Ram et al, who studied risk factor for developing typhoid and concluded that drinking un-boiled water at home was a significant risk factor and using a latrine for defecation was significantly protective. (15) However, this may be explained by improper hygiene of the mother and the latrine may be present and not used by the child. Ashbolt et al and Kumar et al stated that poor water quality, sanitation and hygiene account for 1.7 million deaths a year world-wide. (15, 16) Poverty, uncontrolled urbanization and inadequate infrastructure all contribute to the contamination of water supplies.

Family history of typhoid was present in 34.6% of stool carriers and 12.5% of urinary carriers. Camilo et al conducted a ffamily study in Santiago, Chile, during an era of high typhoid endemicity in order to ascertain whether chronic carriers were significantly more frequent in households where there were index cases of children with typhoid fever than in matched control households. They had found that chronic carriers were significantly more frequent in households where there was a case of typhoid in the house. (13)

Symptoms suggesting typhoid fever was present in 58.6% of stool carriers and 18.2% in urinary carriers. Abdominal pain was present in 60% of stool carriers and 75% of urinary carriers, jaundice are present in small percentage and history of bilharziasis are present in almost all cases of urinary carriers. These findings are agreed in studies by Amadife et al who stated that the diagnosis of typhoid fever in young children is more difficult than in the adult due to the unusual pattern of presentation. (17) Akpede et al mentioned that in young children and infants the disease may present as a non-specific febrile illness (18) while Brush et al stated that fever occurs in 75-85% of patients. (2)
Conclusion
This study showed that typhoid bacilli were found 18.7% as stool carriers and 3.1% as urinary carriers. The stool carriers to urinary carriers are 6 to 1 ratio. Highest percentage of carriers was at age above 12 years. Chronic stool and urinary carriers were more in rural than urban areas. This high percentage may be due to bad water supply and sewage disposal in the rural areas than in the urban. Family history of typhoid was present in 34.5% of stool carriers and 14.7% of urinary carriers. Symptoms suggesting typhoid fever was present in 58.6% of stool carriers and 18.2% in urinary carrier.

In conclusion: Chronic typhoid carriers are present in considerable percentage in pediatric age group in Sohag. The effect of this carrier state in incidence of typhoid fever in Sohag should be investigated.
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Last Updated : Sunday, July 01, 2007 Vol 4 Issue 7 Art #26
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AbdelRaheem M N, Y.Yousef G, M.Shalaby H, Eltorky M, AbdelAzziz A. TYPHOID CARRIERS AMONG CHILDREN IN SOHAG. Pediatric Oncall [serial online] 2007[cited 2007 July 1];4. Art #26. Available From : http://www.pediatriconcall.com/Journal/Article/FullText.aspx?artid=166&type=J&tid=&imgid=&reportid=302&tbltype=
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