While reinfection may occur, it is still recommended that regular treatments be conducted as it will minimize the occurrence of chronic outcomes. There are also increasing concerns about the issue of drug resistance. Drug resistance has appeared in front-line anthelmintics used for livestock nematodes. Generally human nematodes are less likely to develop resistance due to longer reproducing times, less frequent treatment, and more targeted treatment. Nonetheless, the global community must be careful to maintain the effectiveness of current anthelmintic as no new anthelmintic drugs are in the late-stage development. Epidemiology
It is estimated that between 576 and 740 million individuals are infected with hookworm. Of these infected individuals, about 80 million are severely affected. The major cause of hookworm infection is N. americanus which is found in the Americas, sub-Saharan Africa, and Asia. A. duodenale is found in more scattered focal environments, namely Europe and the Mediterranean. Most infected individuals are concentrated in sub-Saharan Africa and East Asia/the Pacific Islands with each region having estimates of 198 million and 149 million infected individuals, respectively. Other affected regions include: South Asia (50 million), Latin America and the Caribbean (50 million), South Asia (59 million), Middle East/North Africa (10 million). A majority of these infected individuals live in poverty-stricken areas with poor sanitation. Hookworm infection is most concentrated among the worlds poorest who live on less than $2 a day.While hookworm infection may not directly lead to mortality, its effects on morbidity demand immediate attention.
When considering disability-adjusted life years (DALYs), neglected tropical diseases, including hookworm infection, rank among diarrheal diseases, ischemic heart disease, malaria, and tuberculosis as one of the most important health problems of the developing world. It has been estimated that as many as 22.1 million DALYs have been lost due to hookworm infection. Recently, there has been increasing interest to address the public health concerns associated with hookworm infection. For example, the Bill & Melinda Gates Foundation recently donated US$34 million to fight Neglected Tropical Diseases including hookworm infection. Former US President Clinton also announced a mega-commitment at the Clinton Global Initiative (CGI) 2008 Annual Meeting to de-worm 10 million children.Many of the numbers regarding the prevalence of hookworm infection are estimates as there is no international surveillance mechanism currently in place to determine prevalence and global distribution. Some prevalence rates have been measured through survey data in endemic regions around the world. The following are some of the most recent findings on prevalence rates in regions endemic with hookworm. Darjeeling, Hooghly District, West Bengal, India (Pal et al. 2007)
43% infection rate of predominantly N. americanus although with some A. duodenale infection
Both hookworm infection load and degree of anemia in the mild rangeXiulongkan Village, Hainan Province, China (Gandhi et al. 2001)
60% infection rate of predominantly N. americanus
Important trends noted were that prevalence increased with age (plateau of about 41 years) and women had higher prevalence rates than menHòa Bình, Northwest Vietnam (Verle et al.