Typhoid or enteric fever is caused by Salmonella serotype typhi and paratyphi. It is one of the major public health problem in developing countries including Nepal. In recent years, increased urbanization and growing population within Kathmandu valley, attributed mainly to improper sanitary condition and fecal contamination of drinking water. These all factors contributes to a very high prevalence of typhoid fever through out the country.
This study was laboratory based study carried out six month period from march 2017 to August 2017 at microbiology lab in Nepal Medical college.
Results and conclusion
In the present study, the prevalence of enteric fever is mainly caused by Salmonella. Typhi than Salmonella Paratyphi A was observed.
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Copyright © 2023 Kirtika Gautam
The authors have declared that no competing interests exist.
Typhoid fever is caused by the bacteria Salmonella Typhi and Salmonella Paratyphi. Due to ingestion of food and water usually contaminated by urine or feces of infected carriers. Typhoid fever is life threatening systemic illness and a major public health problem in many countries including Nepal. Likewise, it is an acute and invasive infection of the gastro intestinal system. This disease is more prevalent in children and young adults 1.
In Nepal, typhoid fever is common in all populated areas. In recent years, increased urbanization, and growing population density within the major cities and the widespread lack of access to clean water and food have lead to a high prevalence of typhoid through out the country 2. In Nepal typhoid fever, commonly known as bisham jwar. It is prevalent in mountains,valley and southern terai region as an endemic. Its peak incidence occuring from from May to August. In Nepal salmonella serovar is the most common single pathogen isolated in blood cultures.
Prior reports from Kathmandu link low socioeconomic status and unsanitary living condition to higher prevalence of typhoid fever. The disease is characterized by prolonged fever, abdominal distension, constipation, headache, rash, malaise, loss of appetite, nausea, vomiting and leukopenia. 3
Approximately, 10% of patients recovering from typhod fever excrete Salmonella Typh in the stool for three month and in the past 2 to 3% become permanent carrier. These infections have great potient for epidemic spread therefore
To find out the more prevalent types of salmonella serovar in typhoid fever.
To find out the genderwise distribution of salmonella serovar in typhoid fever.
To find out the seasonal variation of Salmonella serovaer in typhoid fever.
Inclusion and exclusion criteria
In this study, patients clinically suspected of typhoid fever were enrolled.
The patients already have antibiotics treatment and
Repeated samples from the same patient were excluded.
Material and methods
Blood samples from typhoid fever suspected patients were collected.
Alltogethers 400 patients suspected of having typhoid fever were collected at Nepal Medical College (NMC). Different age group and sex visiting in Microbiology Laboraory for blood culture were included in the study from April to September 2017.Blood samples were collected aseptically. Samples collecting site were also make sterile with 70% alcohol.
Specimen collection, processing and identification of Salmonella isolates
Blood collection for paediatric patients was 3 ml and 5 ml for adults patients were collected and incubated into Brain Heart Infusion (BHI) broth at the ratio of d1:10. After incubation at 37℃ for 24 hours. After 24 hours of incubation, if there is seen turbidity in BHI broth, it was then sub culture into MacConkey agar, blood agar and chocolate agar respectively.4
Next day, if there was seen non lactose fermenter pale colour colonies then it was further confirmed bu using standard mocrobiological techniques. Such as biotyping e.g. colony morphology, staining reaction and biochemical characteristics and serotypng using specific atisera i.e. Denka Seiken Co. ltd., Tokyo, Japan. Likewise patients information such as patient name. age. Sex. Ward, bed no (if admitted), brief clinical history, duration of hospital stay and histroy of antibiotic use were taken.
Specimens were handled, processed and disposed by using standard guidelines for biohazardous materials. Spills was immediately disinfected.
A positive control and a negative control were included in each run.
The study subjects was suspected typhoid fever patients visiting in Nepal Medical College, jorpati. In this study, total 400 blood samples were proceed both from out patients and inpatients visiting in hospital. In this study, male population were more infected (60%) than female population (40%) (Table 1). Likewise, in total isolated cases (200) of Salmonella spp, Salmonella typhi (180) was more prevalent organism than Salmonella paratyphi A (Figure 1).Table 1. Distribution of typhoid fever according to gender
Figure 1.Prevalence of Salmonella typhi and Salmonella paratyhi A isolated from blood
Nepal is a pocket area of typhoid endemic city due to cross contamination of food and drinking water with sewage and poor sanitation status. Estimation of the disese burden and its etiology would be helpful in the development of effective prevention and control intervention 5. Out of 200 cultures confired typhoid fever cases, 180 were caused by salmonella typhi and 20 were by Salmonella Para Typhi. Such a higher prevalence of typhi serovars in our study complies with the study by Adhikari et al, (64%) and (35.9%) of Salmonella and Salmonella respectively 6. In accordance to this study such a high prevalence of Salmonella Typhi was due to contaminated drinking water supply ia small Nepali town has recently been described 11. However Shirawa et al documented Salmonella Paratyphi are more prevalent serovar in Kathmandu, Nepal 7. Which is suppported by another study of Pramod et al., (35.9%). Salmonella and (64.1%) Salmonella Paratyphi 8. Although, there is no such well established cause of serovar vriation in tyhphoid cases. Higher incidence of Salmonella Typhi might be due to waterborne transmission of Salmonella Typhi as it usually involves smaller inocula than paratyphoid achieved through food borne transmission that require large inocula 9.
In accordance to this study, more prevalent rate of typhoid cases was in male than females 10. Which was done by Mohantyet al 2006 in All iIndia institute of Medical science. The one of the strong reason for such a high rate in males were that males in Nepal, at present also usually worked outside their homes and also eat street food and drinking water are liable to contaminated.
This study shows the frequency of typhoid fever is higher in male population compared to female population. Likewise, the result of this investigation shows the prevalence organism for causing typhoid fever is Salmonella typhi than Salmonella partyphi A. It might be due to the reason that salmonella typhi requires smaller number to cause the disease. But for causing partyphoid fever, the causative organism i. e. Salmonella paratyphi A requires only the small numbers.
List of abbreviation
I am grateful to all the staff of microbiology department for their great suppotive help during this research work.
Source of support
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- 3. (1998) Environment & Public health organiztion. ENPHO [Internet].Available: http:enpho.org.featured-typhoid-the neglected-urgent-in-nepal
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