**4.6 Strengthening of institutional capacities**

The integration of control activities within the health services is fundamental for the sustainability of the programme. However, most of the existing structures do not have the capacity to ensure the implementation of these activities, leading to programme failure. Therefore, the strengthening of the health system is a requirement for the long-term viability of the control programme. Furthermore, an efficient participation of schools and communities in the disease control requires a reinforcement of capacity of the school system and the community ownership.

#### **4.7 Operational research**

It is important to support operational research to fulfill gaps and improve the implementations of the control. For example, the understanding of some key issues, such as baseline epidemiology, morbidity assessment, drug efficacy testing and monitoring of drug resistance, is of vital importance.

### **4.8 Monitoring and evaluation**

Regular monitoring and evaluation are necessary to ensure that programmes are efficiently implemented and that the beneficiaries gain the maximum benefit. This is particularly challenging given the diversity of tools and indicators. Substantial progress has been made towards the development of standardized tools for monitoring and evaluating NTD control programmes. WHO is currently developing guidelines based on the experience to date with integrated preventive chemotherapy interventions.

### **4.9 Better diagnostic tools**

Because of its simplicity and relatively low-cost, the Kato–Katz technique (Katz et al., 1972) is widely used for epidemiological field surveys and is recommended by the WHO for surveillance and monitoring of schistosomiasis and STH control programmes (WHO, 1991; Montresor et al., 1998). Though the specificity is very high, the sensitivity of Kato–Katz in single stool sample examination is limited by day-to-day variation in egg excretion leading to measurement error in estimating the presence of infection. This is particularly accentuated in areas with high proportions of light intensity infections (Hall, 1981; Booth et al., 2003; Tarafder et al., 2009). In the current era of preventive chemotherapy, the intensification of large-scale interventions and repeated mass deworming will significantly reduce the prevalence and intensities of schistosomiasis and STH infections (Savioli et al., 2004; Kabatereine et al., 2007). As consequence of the increase of low-intensity infections, more light infections will be often missed if single stool samples are examined by Kato–Katz method, resulting in high underestimation rates. Therefore, there is a need to develop and

Control of Schistosomiasis and Soil-Transmitted

for schistosmiasis and STH elimination.

the successful control of schistosomiasis and STH in Cameroon.

**6. Acknowledgements** 

**7. References** 

knowledge and experiences.

**5. Conclusion** 

Helminthiasis in Sub-Saharan Africa: Challenges and Prospects 371

opportuny to take up the challenge, to be more ambitious and to move from control to elimination where feasible. To do this there is a need to adapt the current threshold for intervention (i.e. prevalence > 10%) and to carefully define the implementation unit for PZQ mass administration. Treatment algorithms should be re-defined based on current

During the past several decades, many attempts have been made to control schistosomiasis, STH and other NTDs. Important advances have been made such as the development of praziquantel, albendazole and mebendazole, the current drugs of choice for these NTDs, which amplified treatment possibilities to the majority of people who need it. Although few control successes were achieved, the global objective is long way off and these diseases remain important public health problems in developing countries. Fulfilling the mandate of the World Health Assembly resolution 54.19 will require the regular treatment of hundreds of millions of children over decades. A successful control of schistosomiasis and STHs across the endemic regions calls for strengthening health system and interventions, ensuring access to anthelminthic drugs in all health services, co-implementation and the coordinated use of the different anthelminthic drugs, promotion of access to safe water, adequate sanitation and health education, and mobilization of resources to sustain control activities. The challenge also includes an improvement of drug efficacy for a much better rapid impact. Indeed, the low cure rate of the recommended drugs for STH, at the single dose as commonly used, highlights the need for an alternative strategy based either on a multipledays treatment regimen, an alternating use of albendazole and mebendazole from one deworming round to another, or the use of an alternative drug. A multiple day treatment would obviously increase the costs, but the immediate and long-term benefits would be priceless. Today, there exist new impetus to global helminth control and a series of favourable factors for implementing successful control programmes. There are several and increasing funding opportunities, and we have a great opportunity to properly take up the challenge and relieve poor communities from disease burden that jeopardise their development. There is an urgent need for well co-ordinated and transparent use of multisource funds to increase efficiency and to avoid duplication of efforts. We should act cautiously and address the dilemma between costs and efficacy of interventions, and between control and elimination. Time is right to act more ambitiously and to set the agenda

The author gratefully acknowledges all partners and stakeholders who contribute towards

Amazigo, U.V., Obono, O.M., Dadzie, K.Y., Remme, J., Jiya, J., Ndyomugyenyi, R., Roungou,

J.B., Noma, M., Sékétéli, A. (2002). Monitoring community-directed treatment programmes for sustainability: lessons from the African Programme for Onchocerciasis Control (APOC). *Ann. Trop. Med. Parasitol*. 96 (Suppl. 1), S75–S92.

validate more sensitive diagnostic tools for accurate surveillance and monitoring of schistosomiasis and STH control programmes, and for monitoring of drug efficacy. Some studies recommended multiple stool samples in order to avoid underestimating the 'true' prevalence and transmission potential of schistosomiasis and STH infections. Indeed, it was demonstrated that Kato–Katz examination of 3 instead of 1 stool specimen increased the sensitivity of helminth diagnosis, most notably for hookworm (Steinmann et al., 2008; Knopp et al., 2008) and intestinal schistosomiasis (De Vlas and Gryseels, 1992; Lin et al., 2008). Recent studies suggested that urine circulating cathodic antigen (CCA) assays maybe an appropriate test for the diagnosis of *S. mansoni* in moderate transmission zones (Shane et al., 2011; Stothard et al., 2011; Tchuem Tchuenté et al., 2012). Several alternative stool examination techniques have been tested for the detection of STH infections. FLOTAC, a new technique mainly used in the veterinary field, was suggested as a suitable diagnostic tool particularly in situations of low parasite infection intensities (Cringoli, 2006). Recent studies found that a single FLOTAC examination was more sensitive than triplicate Kato– Katz thick smears for the diagnosis of low-intensity STH infections (Knopp et al., 2009). In particular, the FLOTAC technique improves the ability to diagnose human hookworm infections accurately (Utzinger et al., 2008), which is generally underestimated when using Kato–Katz thick smears due to a rapid disintegration of hookworm eggs and the constraint to read the slides very shortly (within 30 min) after preparation (Dacombe et al., 2007). FLOTAC was thus suggested as a suitable method for a rigorous surveillance of helminth control programmes, monitoring of STH transmission and verification of local elimination (Knopp et al., 2009). McMaster, another flotation technique commonly used in veterinary parasitology, is an alternative diagnostic tool. The results of a comparative study of four techniques, i.e. ether-based concentration, Parasep Solvent Free, McMaster and FLOTAC, showed that despite the fact that McMaster was less sensitive than FLOTAC, the former technique was the most feasible and easy to perform under field conditions. McMaster appeared as a promising technique of choice when using fecal egg counts for monitoring of drug efficacy against STHs (Levecke et al., 2009). Overall, several techniques are available for the detection of STH infections, with significant difference in the cost, sensitivity, simplicity and field applicability. Though a true 'gold standard' test with 100% accuracy does not exist, Kato–Katz thick smears is so far commonly and widely used as the basic and 'default' technique for helminth epidemiology, despite some limitations.

Further efforts should be made to validate other detection tools (Tchuem Tchuenté, 2011). The choice of a specific diagnostic assay should be governed by the objective of the activity, and according to the stage of helminth control (Berquist et al., 2009). As the accuracy of a given diagnostic technique may vary significantly according to helminth transmission level, tools should be adapted when moving from morbidity control to elimination of infection. Moving toward the surveillance and elimination phases requires more sensitive techniques such as antibody detection. However, sero-diagnostic tools for detection of helminth infections require blood sample collection (invasive), access to affordable, high-quality reagents; which are important limiting factors for their integration into large-scale national control programmes. These are probably some of the reasons why today only a few countries have adopted antibody detection as a key strategy in helminth diagnosis (Berquist et al., 2009).

#### **4.10 New paradigm shift: Moving from control to elimination**

In the past years, the costs of PZQ and the lack of resources were major constraints for the control of schistosomiasis. Today, there exists new impetus for the control, with increasing funding opportunity and donated PZQ by pharmaceutical companies. Therefore, there is an opportuny to take up the challenge, to be more ambitious and to move from control to elimination where feasible. To do this there is a need to adapt the current threshold for intervention (i.e. prevalence > 10%) and to carefully define the implementation unit for PZQ mass administration. Treatment algorithms should be re-defined based on current knowledge and experiences.
