**3.1 Progress towards the 2010 global target**

Progress in implementing schistosomiasis and STH control programmes has been slow but steady. Since 2006, there has been an overall increase in the number of people treated for schistosomiasis and STH. The increase in treatments has occurred entirely in the African Region, where the number of people treated more than doubled from 2006 to 2009 (WHO, 2011). This number increased by 93% in 2010. The increase in the number treated suggests that both governments and their donor partners are now investing in schistosomiasis control (WHO, 2012). In 2010, 18 over 42 schistosomiasis endemic countries in the African region and 34/46 STH endemic countries or territories reported their treatment data to WHO. Overall, 27,983,327 people were treated for schistosomiasis, and 91,025,863 children for STH (Table 1).


Table 1. African Regional summary of children treated for schistosomiasis and STH, 2010

Control of Schistosomiasis and Soil-Transmitted

Helminthiasis in Sub-Saharan Africa: Challenges and Prospects 363

(A)

(B)

Fig. 1. Comparative status of schistosomiasis control in Africa at the end of the 20th century

(A) and in 2010 (B).

Figure 1 illustrates the progress in Africa ten years after the 2001 WHA resolution. Although significant progress has been made over the past years to significantly reduce schistosomiasis and STH infection prevalence below low risk, or to regularly implement mass drug administration (MDA) in several countries, the global achievement is still very far from the WHO's target of regular deworming of at least 75% of school-age children at risk. Indeed, from the data of epidemiological coverage of STHs, it was estimated that only 15% of school-aged children at risk of infection have been treated with preventive chemotherapy in 2008 (WHO, 2010). School-based deworming interventions still cover only a minority of children considered to be at risk despite the low cost of these interventions and their significant impact on health. More worrying, the number of people treated for schistosomiasis in Sub-Saharan Africa is estimated to be only 6.71% of the people infected (WHO, 2011). The major constraint to controlling schistosomiasis continues to be the limited access to praziquantel (Hotez et al., 2010). In the African Region, only few countries (18 in 2008) have achieved the 75% treatment target.

#### **3.2 Taking advantage of integrated control of NTDs**

In the developing world, polyparasitism is the norm rather than the exception (Molyneux et al., 2005; Fleming et al., 2006; Tchuem Tchuenté et al., 2003). In large parts of the world, particularly in Africa, most children are infected by more than one species of helminth. These NTDs frequently overlap geographically and they impose a great burden on poor populations, affecting the same individuals. Therefore, the current strategy for NTD control is to integrate interventions for multiple diseases (Molyneux et al., 2005). This integrated approach is the basis for cost-effectiveness and streamlined efficiency. Also, because many of the drugs used for mass treatment are provided free of charge by major multinational pharmaceutical companies, the MDA approach is the most cost-effective global public health control measure (Hotez et al., 2007). Schistosomiasis and STH infections are the most prevalent and widespread of the common NTDs, and they overlap in many parts with many of the other NTDs. Therefore, an integration of schistosomiasis and STH control with other helminth control programmes and a good coordinated use of (donated) drugs would be highly beneficial for their control. This would indeed allow to take advantage of drug donation and co-administration, and to optimize the preventive chemotherapy.

Within the past decade, significant progress has been made on large-scale treatment of schistosomiasis and STH through integrated control with other NTDs, thanks to a number of international organizations, donor foundations, bilateral institutions and nongovernmental organizations that responded to the 2001 WHO's call for action (Savioli et al., 2009). With a support from the American (USAID) and British (DFID) governments, as well as the Bill and Melinda Gates Foundation, the pharmaceutical industry, and many not-for profit organizations, millions of children are regularly treated for schistosomiasis, STH and other NTDs. Today, an integrated control of NTD using the preventive chemotherapy is operating in more than 15 countries. Within the first three years (2006-2009) of implementation of the USAID NTD Control Program, the number of persons reached each year increased progressively, with a cumulative total of 98 million persons receiving 222 million treatments (Linehan et al., 2011). In West Africa, nearly 13.5 million doses of albendazole have been administered against STH between 2004 and 2006 in Burkina Faso, Mali and Niger, with coverage rates varying between 67.0% and 93.9% (Garba et al., 2009). Monitoring and evaluation activities after large-scale administration of praziquantel for schistosomiasis and albendazole for STH showed a significant decrease in the intensity of infections. Also, there was a significant increase in haemoglobin concentration after 1 and 2

Figure 1 illustrates the progress in Africa ten years after the 2001 WHA resolution. Although significant progress has been made over the past years to significantly reduce schistosomiasis and STH infection prevalence below low risk, or to regularly implement mass drug administration (MDA) in several countries, the global achievement is still very far from the WHO's target of regular deworming of at least 75% of school-age children at risk. Indeed, from the data of epidemiological coverage of STHs, it was estimated that only 15% of school-aged children at risk of infection have been treated with preventive chemotherapy in 2008 (WHO, 2010). School-based deworming interventions still cover only a minority of children considered to be at risk despite the low cost of these interventions and their significant impact on health. More worrying, the number of people treated for schistosomiasis in Sub-Saharan Africa is estimated to be only 6.71% of the people infected (WHO, 2011). The major constraint to controlling schistosomiasis continues to be the limited access to praziquantel (Hotez et al., 2010). In the African Region, only few countries (18 in

In the developing world, polyparasitism is the norm rather than the exception (Molyneux et al., 2005; Fleming et al., 2006; Tchuem Tchuenté et al., 2003). In large parts of the world, particularly in Africa, most children are infected by more than one species of helminth. These NTDs frequently overlap geographically and they impose a great burden on poor populations, affecting the same individuals. Therefore, the current strategy for NTD control is to integrate interventions for multiple diseases (Molyneux et al., 2005). This integrated approach is the basis for cost-effectiveness and streamlined efficiency. Also, because many of the drugs used for mass treatment are provided free of charge by major multinational pharmaceutical companies, the MDA approach is the most cost-effective global public health control measure (Hotez et al., 2007). Schistosomiasis and STH infections are the most prevalent and widespread of the common NTDs, and they overlap in many parts with many of the other NTDs. Therefore, an integration of schistosomiasis and STH control with other helminth control programmes and a good coordinated use of (donated) drugs would be highly beneficial for their control. This would indeed allow to take advantage of drug

donation and co-administration, and to optimize the preventive chemotherapy.

Within the past decade, significant progress has been made on large-scale treatment of schistosomiasis and STH through integrated control with other NTDs, thanks to a number of international organizations, donor foundations, bilateral institutions and nongovernmental organizations that responded to the 2001 WHO's call for action (Savioli et al., 2009). With a support from the American (USAID) and British (DFID) governments, as well as the Bill and Melinda Gates Foundation, the pharmaceutical industry, and many not-for profit organizations, millions of children are regularly treated for schistosomiasis, STH and other NTDs. Today, an integrated control of NTD using the preventive chemotherapy is operating in more than 15 countries. Within the first three years (2006-2009) of implementation of the USAID NTD Control Program, the number of persons reached each year increased progressively, with a cumulative total of 98 million persons receiving 222 million treatments (Linehan et al., 2011). In West Africa, nearly 13.5 million doses of albendazole have been administered against STH between 2004 and 2006 in Burkina Faso, Mali and Niger, with coverage rates varying between 67.0% and 93.9% (Garba et al., 2009). Monitoring and evaluation activities after large-scale administration of praziquantel for schistosomiasis and albendazole for STH showed a significant decrease in the intensity of infections. Also, there was a significant increase in haemoglobin concentration after 1 and 2

2008) have achieved the 75% treatment target.

**3.2 Taking advantage of integrated control of NTDs** 

Fig. 1. Comparative status of schistosomiasis control in Africa at the end of the 20th century (A) and in 2010 (B).

Control of Schistosomiasis and Soil-Transmitted

Helminthiasis in Sub-Saharan Africa: Challenges and Prospects 365

start-up country for mebendazole donation in Africa. Indeed, in 2005 Johnson & Johnson established a partnership with the Task Force for Child Survival and Development (currently The Task Force for Global Health) to develop a programme to donate mebendazole via a multi-disciplinary initiative designed to address intestinal worm infections in the most at-risk children of the world. Cameroon was selected as the start-up country for this drug donation programme because of its leadership and commitment to eliminating infections as a major public health problem (http://www.janssenpharmaceutica.be/download\_Cameroen\_N.asp). With regard to control, a pilot phase was completed in February 2006 in one health district, where approximately 20,000 school-aged children were treated with praziquantel and albendazole. Subsequently, the activities were extended to one entire region of the ten regions in Cameroon, i.e. the Adamawa region in the northern part of the country. This was implemented with support from partners, including the World Food Programme (WFP), the Canadian Co-operation, the United Nations International Children's Emergency Fund (UNICEF) and SCI/Medpharm (which donated the drugs praziquantel and albendazole). Deworming was conducted in all 500 primary schools in this region, and approximately 150,000 school-aged children were treated in May 2006. Overall, 700 head teachers, 500 representatives of parent teacher associations, and 2500 teachers were trained. In addition, parasitological surveys for schistosomiasis and STH were conducted in 40 selected schools

where stool and urine samples were collected from a total of 1830 children.

twice a year (Tchuem Tchuenté and N'Goran, 2009).

The mebendazole donation enabled the national control programme to scale-up activities rapidly. As a result, deworming activities were increased to encompass all ten regions. In 2007, Cameroon launched a nationwide deworming campaign, and 4 million school-aged children were treated. The launching ceremony allowed the government and partners to further reaffirm their commitment and to galvanise communities, international development agencies, non-governmental organisations (NGOs) and other stakeholders to join in the effort to implement fundamental improvements in disease control and prevention. The country has in place school-based and community-directed channels and in the programme teachers and community drug distributors administer the drugs to children along with health and hygiene education. The major activities conducted are: (1) training of health and education personnel, (2) sensitization and education of communities about the disease, the risks of infection and measures for prevention, (3) promotion of hygiene, safe water and sanitation systems in communities, and (4) deworming of children. Since 2007, 4 million school-age children are treated annually with mebendazole, with the involvement of over 75,000 trained teachers and head teachers. Control of STH is primarily implemented through school-based distribution of mebendazole, co-administered with praziquantel where schistosomiasis is endemic. In addition, albendazole is co-administered with ivermectin during the community-directed treatment for LF. Furthermore, over 2.7 million children aged 1–5 years are dewormed during child health week campaigns implemented

Moreover, parasitological surveys were conducted in selected schools in all 63 health districts of the Centre, East and West regions of Cameroon, in order to update the disease distribution map, to assess the impact of previous deworming campaigns, and to determine where treatment with PZQ should be extended. The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. In comparison to previous mapping data collected 25 years ago, the results showed an increase of schistosomiasis transmission in several health districts, where PZQ MDA was not implemented so far. On the contrary, there was a significant decline of STH infection

years of treatment (Fenwick et al., 2009). Combination of ivermectin and albendazole, and co-administration of praziquantel and albendazole or mebendazole have been proven to be safe, with no side effects outside those commonly associated with each of these drugs (Horton et al., 2000; Olds et al., 1999). Though WHO does not formally recommends combination of praziquantel and ivermectin yet, recent studies have demonstrated the safety of triple co-administration of praziquantel, albendazole and ivermectin in areas where schistosomiasis, STH and LF or/and onchocerciasis are co-endemic and where several rounds of treatment with one or two drugs have been implemented in the past (Mohammed et al., 2008).

#### **3.3 A country example: Cameroon**

In Cameroon, schistosomiasis and STH are important parasitic diseases. Recent estimates indicate that at least 2 million people are infected with schistosomiasis, 5 million are at risk and more than 10 million are infected with gastrointestinal helminths (Minsante, 2005). In 1983, a pilot project for schistosomiasis control, funded by USAID, was set up. Within this framework a national epidemiological survey of schistosomiasis and STH was conducted between 1985 and 1987. Overall, 49 divisions, 504 schools and 23 850 schoolchildren were investigated. The results showed the occurrence of *S. haematobium, S. mansoni, S. guineensis, A. lumbricoides, T. trichiura* and *N. americanus* as the major helminth species. The highest transmission levels of schistosomiasis occured in the northern part, whereas STH were more prevalent in the southern part of the country (Ratard et al., 1990, 1991; Brooker et al., 2000). When considering all these helminthic diseases, no region of the country is spared. However, this pilot project stopped in 1989 when the USAID support ended.

Taking advantage of the renewed momentum for NTDs, the national programme for the control of schistosomiasis and STH was created in March 2003. There is a strong political commitment from the Ministries of Public Health and Basic Education. These two ministries work in close collaboration and this inter-sectorial engagement is consolidated by the fact that the national steering committee for the control is co-chaired by the Minister of Public Health and the Minister of Basic Education, as president and vice-president, respectively. The Cameroonian proposal for support to SCI was presented by the Minister of Public Health himself who attended the SCI advocacy meeting in London in July 2003. Therefore, the non-selection of Cameroon for SCI support came both as a surprise and a disappointment. Beyond the main ranking criteria, including the existence of a strategic plan for control, the strong political commitment and the quality of the proposal, the SCI selection was finally made on a regional combination of three East African countries and three West African countries, with emphasis on country-regional collaboration and consortium. In spite of this, the Cameroonian government made necessary efforts to ensure the success of the schistosomiasis and STH control, as it was among the priority programmes of the country. Hence, the national control programme was officially launched on 25 March 2004.

The action of the programme during the past few years was intense and multifaceted, with a number of key achievements. Based on the limited resources available, the priority activities were centred on three major activities: (1) the production of various strategic documents necessary for the implementation of the activities and advocacy; (2) the advocacy and the mobilisation of partners and funding; and (3) the implementation of activities in selected areas. A strong emphasis was put on advocacy, the results of which were encouraging for future activities and plans. The most important was the selection of Cameroon as the first

years of treatment (Fenwick et al., 2009). Combination of ivermectin and albendazole, and co-administration of praziquantel and albendazole or mebendazole have been proven to be safe, with no side effects outside those commonly associated with each of these drugs (Horton et al., 2000; Olds et al., 1999). Though WHO does not formally recommends combination of praziquantel and ivermectin yet, recent studies have demonstrated the safety of triple co-administration of praziquantel, albendazole and ivermectin in areas where schistosomiasis, STH and LF or/and onchocerciasis are co-endemic and where several rounds of treatment with one or two drugs have been implemented in the past

In Cameroon, schistosomiasis and STH are important parasitic diseases. Recent estimates indicate that at least 2 million people are infected with schistosomiasis, 5 million are at risk and more than 10 million are infected with gastrointestinal helminths (Minsante, 2005). In 1983, a pilot project for schistosomiasis control, funded by USAID, was set up. Within this framework a national epidemiological survey of schistosomiasis and STH was conducted between 1985 and 1987. Overall, 49 divisions, 504 schools and 23 850 schoolchildren were investigated. The results showed the occurrence of *S. haematobium, S. mansoni, S. guineensis, A. lumbricoides, T. trichiura* and *N. americanus* as the major helminth species. The highest transmission levels of schistosomiasis occured in the northern part, whereas STH were more prevalent in the southern part of the country (Ratard et al., 1990, 1991; Brooker et al., 2000). When considering all these helminthic diseases, no region of the country is spared.

Taking advantage of the renewed momentum for NTDs, the national programme for the control of schistosomiasis and STH was created in March 2003. There is a strong political commitment from the Ministries of Public Health and Basic Education. These two ministries work in close collaboration and this inter-sectorial engagement is consolidated by the fact that the national steering committee for the control is co-chaired by the Minister of Public Health and the Minister of Basic Education, as president and vice-president, respectively. The Cameroonian proposal for support to SCI was presented by the Minister of Public Health himself who attended the SCI advocacy meeting in London in July 2003. Therefore, the non-selection of Cameroon for SCI support came both as a surprise and a disappointment. Beyond the main ranking criteria, including the existence of a strategic plan for control, the strong political commitment and the quality of the proposal, the SCI selection was finally made on a regional combination of three East African countries and three West African countries, with emphasis on country-regional collaboration and consortium. In spite of this, the Cameroonian government made necessary efforts to ensure the success of the schistosomiasis and STH control, as it was among the priority programmes of the country. Hence, the national control programme was officially launched

The action of the programme during the past few years was intense and multifaceted, with a number of key achievements. Based on the limited resources available, the priority activities were centred on three major activities: (1) the production of various strategic documents necessary for the implementation of the activities and advocacy; (2) the advocacy and the mobilisation of partners and funding; and (3) the implementation of activities in selected areas. A strong emphasis was put on advocacy, the results of which were encouraging for future activities and plans. The most important was the selection of Cameroon as the first

However, this pilot project stopped in 1989 when the USAID support ended.

(Mohammed et al., 2008).

on 25 March 2004.

**3.3 A country example: Cameroon** 

start-up country for mebendazole donation in Africa. Indeed, in 2005 Johnson & Johnson established a partnership with the Task Force for Child Survival and Development (currently The Task Force for Global Health) to develop a programme to donate mebendazole via a multi-disciplinary initiative designed to address intestinal worm infections in the most at-risk children of the world. Cameroon was selected as the start-up country for this drug donation programme because of its leadership and commitment to eliminating infections as a major public health problem (http://www.janssenpharmaceutica.be/download\_Cameroen\_N.asp). With regard to control, a pilot phase was completed in February 2006 in one health district, where approximately 20,000 school-aged children were treated with praziquantel and albendazole. Subsequently, the activities were extended to one entire region of the ten regions in Cameroon, i.e. the Adamawa region in the northern part of the country. This was implemented with support from partners, including the World Food Programme (WFP), the Canadian Co-operation, the United Nations International Children's Emergency Fund (UNICEF) and SCI/Medpharm (which donated the drugs praziquantel and albendazole). Deworming was conducted in all 500 primary schools in this region, and approximately 150,000 school-aged children were treated in May 2006. Overall, 700 head teachers, 500 representatives of parent teacher associations, and 2500 teachers were trained. In addition, parasitological surveys for schistosomiasis and STH were conducted in 40 selected schools where stool and urine samples were collected from a total of 1830 children.

The mebendazole donation enabled the national control programme to scale-up activities rapidly. As a result, deworming activities were increased to encompass all ten regions. In 2007, Cameroon launched a nationwide deworming campaign, and 4 million school-aged children were treated. The launching ceremony allowed the government and partners to further reaffirm their commitment and to galvanise communities, international development agencies, non-governmental organisations (NGOs) and other stakeholders to join in the effort to implement fundamental improvements in disease control and prevention. The country has in place school-based and community-directed channels and in the programme teachers and community drug distributors administer the drugs to children along with health and hygiene education. The major activities conducted are: (1) training of health and education personnel, (2) sensitization and education of communities about the disease, the risks of infection and measures for prevention, (3) promotion of hygiene, safe water and sanitation systems in communities, and (4) deworming of children. Since 2007, 4 million school-age children are treated annually with mebendazole, with the involvement of over 75,000 trained teachers and head teachers. Control of STH is primarily implemented through school-based distribution of mebendazole, co-administered with praziquantel where schistosomiasis is endemic. In addition, albendazole is co-administered with ivermectin during the community-directed treatment for LF. Furthermore, over 2.7 million children aged 1–5 years are dewormed during child health week campaigns implemented twice a year (Tchuem Tchuenté and N'Goran, 2009).

Moreover, parasitological surveys were conducted in selected schools in all 63 health districts of the Centre, East and West regions of Cameroon, in order to update the disease distribution map, to assess the impact of previous deworming campaigns, and to determine where treatment with PZQ should be extended. The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. In comparison to previous mapping data collected 25 years ago, the results showed an increase of schistosomiasis transmission in several health districts, where PZQ MDA was not implemented so far. On the contrary, there was a significant decline of STH infection

Control of Schistosomiasis and Soil-Transmitted

Helminthiasis in Sub-Saharan Africa: Challenges and Prospects 367

(A)

(B) Fig. 2. Comparative maps of the overall soil-transmitted helminthiasis prevalence between the years 1985-1987 (A) and 2010 (B) in the Centre, East and West regions of Cameroon.

Sometimes, many people in a country are working for the same thing, but with different targets because there are different donors. Country ownership brings many gains, including development of local capacity and expertise. There should be a strong political commitment to tackle NTDs in endemic countries. Indeed, examples of success stories are from those countries (e.g. Japan, Morocco and China) that had clear ambitious goal, with high government and national commitment, funding mobilization and leadership. For example, in early 1963 STH occurred in Okinawa, Japan at high prevalence up to 40% in adult population. Through the development of an ambitious 'zero parasites' campaign a successful control was conducted and within a period less than 10 years STHs and other

prevalence and intensities in all three regions, with an overall decline of prevalence from 90.06% (95% CI: 89.45-90.63%) to 24.11% (95% CI: 23.37-24.86%). Based on the prevalence data, the continuation of annual or bi-annual MDA for STH was recommended, as well as an extension of PZQ treatment in identified moderate and high risk communities for schistosomiasis (Tchuem Tchuenté et al., 2012). These results show the positive impact of annual deworming campaigns, and illustrate the progressive success of the national programme for the control of schistosomiasis and STH in Cameroon. This is illustrated in Figure 2. Parasitological surveys are in progress in the remaining regions of Cameroon for the update mapping.
