Trends in Parasitology
Volume 22, Issue 12, December 2006, Pages 552-557
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Opinion
Leishmaniasis and poverty

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Leishmaniasis, a neglected tropical disease, has strong but complex links with poverty. The burden of leishmaniasis falls disproportionately on the poorest segments of the global population. Within endemic areas, increased infection risk is mediated through poor housing conditions and environmental sanitation, lack of personal protective measures and economically driven migration and employment that bring nonimmune hosts into contact with infected sand flies. Poverty is associated with poor nutrition and other infectious diseases, which increase the risk that a person (once infected) will progress to the clinically manifested disease. Lack of healthcare access causes delays in appropriate diagnosis and treatment and accentuates leishmaniasis morbidity and mortality, particularly in women. Leishmaniasis diagnosis and treatment are expensive and families must sell assets and take loans to pay for care, leading to further impoverishment and reinforcement of the vicious cycle of disease and poverty. Public investment in treatment and control would decrease the leishmaniasis disease burden and help to alleviate 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.

References (51)

  • M.V. Marlet

    Emergence or re-emergence of visceral leishmaniasis in areas of Somalia, north-eastern Kenya, and south-eastern Ethiopia in 2000–01

    Trans. R. Soc. Trop. Med. Hyg.

    (2003)
  • S. Rijal

    The economic burden of visceral leishmaniasis for households in Nepal

    Trans. R. Soc. Trop. Med. Hyg.

    (2006)
  • G. Yamey et al.

    The world's most neglected diseases

    Br. Med. J.

    (2002)
  • Editorial

    Research versus treatment for neglected diseases

    Lancet

    (2006)
  • P.J. Hotez

    Combating tropical infectious diseases: report of the Disease Control Priorities in Developing Countries Project

    Clin. Infect. Dis.

    (2004)
  • R. Badaro

    A prospective study of visceral leishmaniasis in an endemic area of Brazil

    J. Infect. Dis.

    (1986)
  • United Nations Conference on Trade and Development

    Statistical Profiles of the Least Developed Countries

    (2001)
  • World Bank

    Reducing Poverty in India: Options for More Effective Public Services

    (1998)
  • A. Ranjan

    Risk factors for Indian kala-azar

    Am. J. Trop. Med. Hyg.

    (2005)
  • D. Anoopa Sharma

    The economic impact of visceral leishmaniasis on households in Bangladesh

    Trop. Med. Int. Health

    (2006)
  • J.B. Santos

    Socioeconomic factors and attitudes towards household prevention of American cutaneous leishmaniasis in an endemic area in Southern Bahia, Brazil

    Cad. Saude Publica

    (2000)
  • C. Bern

    Risk factors for kala-azar in Bangladesh

    Emerg. Infect. Dis.

    (2005)
  • R. Kumar

    Kala-azar epidemic in Varanasi district, India

    Bull. World Health Org.

    (1999)
  • P. Barnett

    Virgin soil: the spread of visceral leishmaniasis into Uttar Pradesh, India

    Am. J. Trop. Med. Hyg.

    (2005)
  • Cited by (0)

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