Introduction:

Les parasitoses intestinales constituent un problème de santé publique majeur, notamment dans les zones à ressources limitées (1,2). Elles sont responsables d’une morbidité significative et peuvent être asymptomatiques ou provoquer des diarrhées, malnutrition et complications chez les immunodéprimés (3,4). Typhoid and paratyphoid fever is a bacterial infection, transmitted through ingestion of food and water contaminated with faecal matter and it is caused by systemic infection with Salmonella enterica serovars Paratyphi A, B, and C (Marks et al., 2017). Salmonella is classified into two major groups: the invasive and the non-invasive. The invasive Salmonella, otherwise called typhoidal Salmonellae produce primarily bacteremia febrile illnesses, with prolonged high fever, headache, and malaise being characteristic symptoms (Koul et al., 1993). Without effective treatment, typhoid fevers can lead to altered mental states termed typhoid state (Verghese, 1985), ileus, gastrointestinal bleeding, intestinal perforation, septic shock, and death (Stanaway et al., 2019). The non-invasive Salmonella are termed non-typhoidal Salmonellae and are made up of Salmonella species, which usually cause gastroenteritis (Stanaway et al., 2019).

In Ghana, Typhoid fever is endemic and according to the study conducted by Global Burden of Disease (2017), it is estimated that, in 2017 alone, there were at least: 69,506 typhoid cases (230 cases per 100,000) and 973 typhoid deaths, 88,981 disability-adjusted life-years lost to typhoid fever (Institute of Health Metrics and Evaluation, 2019). It is also reported that most typhoid cases in Ghana occur in children under the age of 15 years old. A study  conducted by the Typhoid Fever Surveillance in Africa Program (TFSAP) found that typhoid incidence rates among children below the age of 15 years in Asante Akim North, Ghana, were two times higher in children living in  rural than those in urban areas with 636 versus 297 cases per 100,000, respectively (Espinoza et al., 2016) .

Ghana is currently implementing various preventive and control measures against typhoid fever and they include provision of clean water and sanitation, immunization of children under the age of 15 years (Jin et al., 2017); putting in place measures to prevent drug  resistant strain of typhoid fever and strengthening the surveillance system of typhoid fever in the country. Typhoid fever is one of the diseases listed for surveillance according to the Integrated Disease Surveillance and Response (IDSR) strategy in Ghana because of its public health impact characterized by gradual onset of clinical features and the likely misdiagnosis of the disease due to the clinical picture similar to many other febrile illnesses such as malaria (Evans et al., 2004). Additionally, there is no documented evidence of an evaluation on typhoid fever in Wa municipality, hence the need for this evaluation to assess whether the typhoid fever surveillance system in Wa municipality was meeting its set objectives; assess its usefulness and its attributes.

Methods

Study design and area

This was a cross-sectional surveillance system evaluation conducted from 6^th to 30^th June, 2022, in Wa Municipality, Ghana, covering the period from January 2017 to December, 2021.

Figure 3: Typhoid fever trend, Wa municipal, 2017 - 2021

Figure 4: Distribution of typhoid fever cases in Wa Sub municipalities, 2017 – 2021

The typhoid fever surveillance system demonstrated its usefulness by:

Table 4: Geographical representativeness of typhoid fever, WA municipality, 2017 - 2021

Table 5: Typhoid fever representativeness by age and sex, WA municipality, 2018 – 2021

Discussion

We evaluated the typhoid fever surveillance system to establish whether it was meeting its set objectives, its usefulness and attributes. Between 2017 and 2021, the surveillance system detected 19,418 suspected cases of typhoid fever and of this number, 16,552 samples were sent to the laboratory for confirmation and 464 cases tested positive. However, the annual reports did not document any outbreak during the period under review. The highest number of cases were reported from Wa South sub municipal with 7492, followed by Kambali sub municipal with 4297, Dobile recorded 4133, Wa North reported 1767 cases, Bamahu recorded 1269, Kperisi recorded 204, Kpongu had 161 cases, Charingu reported 57, Busa and Charia sub municipals both recorded the lowest number of cases with each having 19 cases. Through typhoid fever surveillance data, several actions were taken within the period under review and this proved the usefulness of the system.

In this evaluation, 88% (30/34) of the respondents understood the case definition of typhoid fever lower than 98.8% in the typhoid fever surveillance system evaluation conducted in Egypt (Refaey, 2018). The surveillance system that is simple would enable every member of the system to easily contribute to the operation of the system. With regard to flexibility, the present evaluation established that all 100% (11/11) key informants interviewed said the surveillance system was flexible as it was able to adapt to any changes during the period under review. This finding was in agreement with the surveillance system evaluation conducted in Republics of the former Soviet Union (Wuhib et al., 2002). Flexibility of the system is important as it allows the system to be reviewed by adding necessary information to it or removing some parts of the system that hinders its smooth operation (Mushtaq et al., 2020). In the current evaluation, we found timeliness of reporting to be on average 97.4% for all reporting facilities which meets the target timeliness according to the IDSR compared to 80% timeliness in the evaluation system of the notifiable diseases such as typhoid fever conducted in Zimbabwe (Mairosi et al., 2017). Meeting the targeted timeliness is a good asset for the typhoid fever surveillance system as it suggests that stakeholders have accepted the system and are participating in it. It also means the system is alert and may timely detect any outbreak (Kalil et al., 2021). In terms of acceptability, 82% of stakeholders participate in typhoid fever surveillance system higher than 25% in notifiable disease surveillance system evaluation conducted in South Africa (Benson et al., 2016). The participation of the stakeholders in the surveillance system shows their willingness to accept the system and this promotes effectiveness and efficiency in its operation (Benson et al., 2016). The representativeness of the typhoid fever surveillance system was 100% as the system was able to represent its population by location, age and sex. This finding was to the surveillance system evaluation conducted in Republics of the former Soviet Union (Wuhib et al., 2002). A system that is well representative is a good sign of inclusion of every member of the population it is targeting to serve (Mushtaq et al., 2020).

More than 90% of respondents indicated that the typhoid fever surveillance system was stable as it was able to operate with the available financial, human resources and power supply system slightly higher than 85.5% stability in the typhoid fever surveillance evaluation system conducted in Egypt (Refaey, 2018). A stable surveillance system is important as it is able to collect, manage and provide data without failure using the available financial and human resources and able to operate during unscheduled power outages. Data completeness was 82% (70/85) in 17 sampled health facilities compared to 92% in the evaluation of notifiable disease surveillance system conducted in Zimbabwe (Mairosi et al., 2017).  Data completeness is a good indicator of proper data quality. The implication of poor data quality of the surveillance system is that wrong decisions and policies would be made at all levels of decision making instead of addressing the actual problem (Awekeya et al., 2021).  In the current typhoid fever surveillance system evaluation, the overall positive predictive value (PPV) was 2.8% similar to the positive predictive value (PPV) of 2.7% on the study of typhoid fever conducted in Ethiopia (Wasihun et al., 2015) but lower than PPV of 50% obtained from the typhoid fever surveillance system evaluation conducted Egypt (Refaey, 2018). The low PPV in this evaluation would mean that the disease is low in the population under the surveillance. This would also mean that the intervention measures that have been put in place are working (Nsubuga et al., 2017).

Conclusion

The typhoid fever surveillance system in Wa municipality meets its set objectives and was also useful. The system was simple, flexible, acceptable, timely, representative and stable. However, there was data inconsistency at health facility and low positive predictive value of the system

Recommendations

1. Ensure improved data quality at health facility level by training all the members of staff involved data management and also holding periodic surveillance data review meetings

1. Ensure improved positive predictive value at all levels of data management system

Acknowledgements

We acknowledge Ghana Field Epidemiology and Laboratory Training Programme, School of Public Health, University of Ghana for financial and technical support during the surveillance system evaluation activity. We further thank Upper West Regional Office and Wa Municipality Directorate for their support. We are grateful to Ms. Fortress Yayra Aku for her mentorship throughout the evaluation process.