Trends in Parasitology
OpinionLeishmaniasis and poverty
Section snippets
The link between poverty and poor health
Higher rates of morbidity and mortality, especially related to infectious diseases, are well-recognized concomitants of poverty. Leishmaniasis has strong links with poverty and is generally ranked as one of the ‘most neglected’ diseases [1]. The concept of neglected diseases originally developed to urge investment in development of new drugs to combat infectious diseases such as leishmaniasis, Chagas disease and African trypanosomiasis. An explicit linkage was articulated between the poverty of
The burden of leishmaniasis
Leishmaniasis comprises two major diseases, visceral leishmaniasis (VL), which is fatal if untreated, and the cutaneous form (CL), which can heal spontaneously but leaves disfiguring scars [4]. Leishmaniasis is endemic in 88 countries, with more than 350 million people at risk. The estimated incidence is 2 million new cases per year, 0.5 million VL and l.5 million CL [5]. Visceral leishmaniasis causes an estimated 59 000 deaths annually (a rate surpassed among parasitic diseases only by
Poverty is the major underlying determinant of leishmaniasis
Low per capita incomes (often below $1/day) are reported in studies of leishmaniasis patients in Bihar [12], Nepal [13], Bangladesh [14] and Brazil [15]. However, within poor communities, the association with low income might not be the primary determinant of risk 11, 16, 17. Moreover, the connections between poverty and leishmaniasis risk are mediated through diverse mechanisms (Table 2).
Poverty is associated with ecological factors that increase risk, such as poor housing conditions (cracked
Poverty as a potentiator of leishmaniasis morbidity and mortality
Poverty can also increase disease progression, morbidity and mortality, most pervasively through poor nutrition. A large proportion of children and women in Asia and Africa have poor protein-energy, iron, vitamin A and zinc nutritional status as a result of inadequate intake and, among women, child-bearing and lactation. A poorly nourished person with leishmanial infection is more likely to progress to kala-azar (clinical VL disease) 30, 31. Recent experimental data in protein-energy-, zinc-
Patterns of healthcare seeking
Poverty goes hand in hand with lower levels of education, literacy and understanding of disease processes and treatment options, and can increase the adverse consequences of leishmanial disease. In seeking care for AVL, people tend to use a hierarchical decision structure, beginning with local, unqualified practitioners or religious healers, and only progressing to the formal healthcare system when the serious nature of the disease is certain [38]. In addition to lack of disease recognition,
Stigma and gender
Poor women are doubly disadvantaged, and encounter higher barriers to healthcare and more intense stigma than men [43]. In Afghanistan, mothers with ACL can be prohibited from touching their children to avoid infecting them, and young women with ACL scars are regarded as unmarriageable [24]. A study from Colombia reported that cutaneous ulcers in a woman can be the pretext for abandonment by her husband [42]. In Bangladesh, women hesitate to report illness because they know their husband's
The mutually reinforcing cycle of leishmaniasis and poverty
Poverty and leishmaniasis together create a mutually reinforcing cycle [45] (Figure 1). Compared with diseases such as malaria, diarrhea or pneumonia, the cost of leishmaniasis treatment is high ($30 to $1500 for drug costs alone), and leishmaniasis is therefore an even more important contributor to poverty for affected families. In French Guyana, the cost of CL care was estimated to total 0.13% of the yearly budget of the territory, and 0.43% of its annual social security budget [46]. In
Perspectives
Patients with leishmaniasis belong disproportionately to the segments of the global population with neither voice nor power to influence decision-makers, and least able to afford the high cost of treatment [7]. Public investment in treatment and control would both decrease the disease burden and help alleviate poverty. Indeed, from a societal point of view, active case detection and early treatment cost less than passive detection, because delayed treatment leads to prolonged morbidity, higher
Acknowledgements
We thank our colleagues who provided relevant data from the countries: D. Argaw (Ethiopia), Director General of Health Services (Bangladesh), A. Rabello (Brazil), R. Badaró (Brazil), S. Sundar (India), A.B. Joshi (Nepal), N. Hamid (Sudan), K. Mustafa and R. Reithinger (Afghanistan), I.D. Vélez (Colombia), A. Llanos-Cuentas (Peru) and Q. Saeed (Pakistan). Special recognition is given to P. Desjeux for reading the manuscript and providing us with extremely valuable comments.
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