Leishmaniasis in refugee and local Pakistani populations.The epidemiology of anthroponotic cutaneous leishmaniasis an·thro·po·not·ic cutaneous leishmaniasis n. A form of cutaneous leishmaniasis occurring in urban areas in western and central Asia and characterized by a painless, chronic, dry ulceration that develops from two to eight months after the bite from the was investigated in northwest Pakistan. Results suggested similar patterns of endemicity in both Afghan refugee and Pakistani populations and highlighted risk factors and household clustering of disease. ********** In Central Asia, anthroponotic cutaneous leishmaniasis (ACL See access control list. 1. ACL - Access Control List. 2. ACL - Association for Computational Linguistics. 3. ACL - A Coroutine Language. A Pascal-based implementation of coroutines. ["Coroutines", C.D. ) is commonly caused by Leishmania tropica Leishmania trop·i·ca n. The protozoan that includes subspecies that cause anthroponotic cutaneous leishmaniasis. and characterized by large, chronic, and disfiguring skin ulcers, which often cause severe social stigma Social stigma is severe social disapproval of personal characteristics or beliefs that are against cultural norms. Social stigma often leads to marginalization. Examples of existing or historic social stigmas can be physical or mental disabilities and disorders, as well as . Because ACL is transmitted anthroponotically (i.e., from human to human) by sandflies, the infection can spread rapidly in concentrated populations, particularly under poor housing conditions housing conditions npl → condiciones fpl de habitabilidad housing conditions npl → conditions fpl de logement , i.e., overcrowding overcrowding overcrowding of animal accommodation. Many countries now publish codes of practice which define what the appropriate volumetric allowances should be for each species of animal when they are housed indoors. Breaches of these codes is overcrowding. or lack of protection from bloodsucking blood·suck·er n. 1. An animal, such as a leech, that sucks blood. 2. An extortionist or a blackmailer. 3. A person who is intrusively or overly dependent upon another; a parasite. insects. In Afghanistan, the incidence of endemic but sporadic ACL has dramatically increased during decades of civil war, because of the associated deterioration of the infrastructure and migration (1-3). Less is known about the current distribution of the disease in neighboring neigh·bor n. 1. One who lives near or next to another. 2. A person, place, or thing adjacent to or located near another. 3. A fellow human. 4. Used as a form of familiar address. v. Pakistan, where it has always been widespread but considered "patchy PATCHY - A Fortran code management program written at CERN. " and nonendemic (4). Recently, however, local authorities and nongovernmental health providers have reported an increasing number of ACL cases in Afghan refugee camps (5,6), which causes concern about the potential spread of the disease among the population and local Pakistani villagers. Therefore, a large-scale epidemiologic study epidemiologic study A study that compares 2 groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect; the investigators try to determine if any factor is associated with the health effect was conducted throughout northwest Pakistan to investigate this issue. The Study From December 2002 to March 2003, a study was conducted in 48 Afghan refugee camps and 19 neighboring villages in Balochistan and North-West Frontier Province North-West Frontier Province, province and historic region (1998 pop. 17,554,674), c.41,000 sq mi (106,200 sq km), NW Pakistan, bounded on the N and W by Afghanistan. Peshawar is the capital. (NWFP NWFP North-West Frontier Province (northwest Pakistan) NWFP Northwest Forest Plan NWFP Non-Wood Forest Product ), Pakistan. Refugee camps were selected on the basis of past and present ACL cases reported by healthcare providers. Villages within 1 km of selected camps were included in the survey; if multiple villages were within 1 km of a camp, one with reported ACL cases was randomly selected, although this method may have introduced selection bias. The goal of the study was to estimate the prevalence of ACL in Afghan refugee camps and neighboring Pakistani villages, as well as determine whether refugee camps could be the source of the anecdotal rise in ACL cases in neighboring villages. In each site, 40 households were sampled along east-west and north-south perpendicular transects. Every head of household was interviewed with a standard questionnaire. If a family reported cases of ACL, an interviewer who had been trained in clinical ACL diagnosis asked to inspect the lesions. Because of logistic constraints, no parasitologic confirmation was performed, but lesions caused by organisms other than Leishmania Leishmania /Leish·ma·nia/ (lesh-ma´ne-ah) a genus of parasitic protozoa, including several species pathogenic for humans. In some classifications, organisms are placed in four complexes comprising species and subspecies: L. are rare, and our previous studies have shown that specificity of our clinical diagnosis is 73% 76% (5). The study included 21,046 persons in 48 refugee camps and 7,305 persons in 19 neighboring villages. Overall, 650 persons (2.3%) had ACL lesions only, 1,236 (4.4%) had ACL scars only, and 38 persons had both ACL lesions and scars. Of those with active ACL, the mean lesion number was 2.1 (range 1-16), and the mean lesion duration (to survey date) was 5.1 months (range 0.7 50 months). Using maximum likelihood methods (7), we estimated the average annual force of infection of ACL to be 0.01 per year (10 cases/1,000 persons per year) during the past 6 years. In refugee camps, the prevalence of ACL lesions was 2.7%, and prevalence of scars was 4.2%. In neighboring Pakistani villages, the prevalence of ACL lesions was 1.7%, and prevalence of scars was 4.9%. Lesion prevalence increased with age more markedly among local Pakistanis than Afghan refugees Afghan refugees (known as Muhajir Afghans in South Asia) are people who fled Afghanistan after the Soviet invasion in 1979 and during the civil war that followed. Since the early 1980s to the late 1990s, there were approximately 3 million Afghan refugees staying in until children were 5-6 years of age; then the prevalence of lesions decreased among Pakistanis and was lower than in the Afghan refugee population for all remaining age groups (Figure). These age trends suggest past infection and resultant immunity. Had the disease been introduced more recently, the risk of ACL would not be expected to be related to age, since everyone would be susceptible to infection (8). However, the low prevalence of scars relative to the number of active lesions, especially among adults, suggests that the disease has been endemic in the region for a short period of time and that transmission may be characterized by a prolonged epidemic similar to that found in Kabul (2,4). To examine the association with potential risk factors and to take clustering of persons within households into account, univariate odds ratios (OR) were estimated by logistic regression In statistics, logistic regression is a regression model for binomially distributed response/dependent variables. It is useful for modeling the probability of an event occurring as a function of other factors. with robust standard errors. We used backward stepwise stepwise incremental; additional information is added at each step. stepwise multiple regression used when a large number of possible explanatory variables are available and there is difficulty interpreting the partial regression multiple logistic regression to identify significant explanatory risk factors while controlling for other variables. Spatial clustering of ACL was investigated at the household and village levels. The degree of within-household clustering was calculated by using a random-effects model fitted to a logistic regression to account for the nonindependence of persons within households. The analysis was conducted using STATA 8 (Stata Corporation, College Station, TX). The nonparametric Mantel correlation statistic with Mantel 2 (Queensland University of Technology, Brisbane, Australia) was used to assess spatial correlation in prevalence between settlements by investigating the relationship between differences in lesion prevalence and geographic distances. The univariate analysis showed that an increased risk of ACL lesion was associated with years lived in camp or village, a family member visiting Afghanistan in the last 12 months, household members with ACL lesions, household members having ACL scars, age group, household with stone walls, crowding in the household (i.e., the number of people per room), having cows in a compound, and having dogs in a compound (Table 1). The same variables were significantly associated with the risk of having an ACL scar, with the exception of a family member's having visited Afghanistan in last 12 months. Use of a mosquito mosquito (məskē`tō), small, long-legged insect of the order Diptera, the true flies. The females of most species have piercing and sucking mouth parts and apparently they must feed at least once upon mammalian blood before their eggs can net was associated with an increased risk of having a scar. Multivariate analysis multivariate analysis, n a statistical approach used to evaluate multiple variables. multivariate analysis, n a set of techniques used when variation in several variables has to be studied simultaneously. showed that younger age, as well as ACL lesions in other household members, increased the risk of an ACL lesion (Table 2). Increased risk of an ACL scar was associated with younger age, living in a refugee camp, and scars in other household members. No significant interactions were detected among the other variables included in the analysis. Finally, after age, sex, and household factors were adjusted for, the random effects model In statistics, a random effect(s) model, also called a variance components model is a kind of hierarchical linear model. It assumes that the data describe a hierarchy of different populations whose differences are constrained by the hierarchy. found evidence for significant household clustering of active ACL cases: [rho] = 0.54 (95% confidence interval confidence interval, n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. [CI] 0.49-0.59, p < 0.0001). ACL scars clustered in households to an even greater degree: [rho] = 0.62 (95% CI 0.59-0.65, p < 0.05). The prevalence of ACL lesions showed a marked variation (0%-21.9%) between Afghan refugee camps and neighboring Pakistani villages. However, analysis using the Mantel correlogram indicated no spatial structuring of ACL between neighboring villages, which emphasizes the highly focal distribution of ACL transmission at the village level and corroborating significant household clustering of ACL. Conclusion The analysis of putative Alleged; supposed; reputed. A putative father is the individual who is alleged to be the father of an illegitimate child. A putative marriage is one that has been contracted in Good Faith and pursuant to ignorance, by one or both parties, that certain risk factors for ACL indicated that living in a stone house reduced the risk, whereas the presence of cows and dogs increased it (Table 2). Although dogs have been found infected with L. tropica (9), they are probably not leishmaniasis leishmaniasis (lēsh'mənī`əsĭs), any of a group of tropical diseases caused by parasitic protozoans of the genus Leishmania. reservoirs, as transmission of L. tropica is thought to be anthroponotic (2). Instead, dogs and other domestic animals represent an additional feeding source for sandflies, which increases contact between vectors and humans. Improved housing protects against vector-borne diseases vector-borne disease Infectious diseases Any infection, usually transmitted by insects–eg, ticks–eg, Lyme disease, Rocky Mountain spotted fever, ehrlichiosis, Colorado tick fever; mosquitos–eg, California-or La Crosse, St Louis, Eastern, Western , since it reduces human-vector exposure. Reported household use of a mosquito net was associated with increased risk of ACL scar, which may reflect the practice of selling insecticide-treated nets at highly subsidized sub·si·dize tr.v. sub·si·dized, sub·si·diz·ing, sub·si·diz·es 1. To assist or support with a subsidy. 2. To secure the assistance of by granting a subsidy. prices to refugee households with active ACL. Although parasite parasite, plant or animal that at some stage of its existence obtains its nourishment from another living organism called the host. Parasites may or may not harm the host, but they never benefit it. identification was not carried out in this study, that L. tropica is the etiologic agent seems probable because it causes most leishmaniasis cases in Central Asia (5,10), and transmission is characterized by clustering of cases and higher risk among children. Our data indicate that parasite transmission is autochthonous autochthonous /au·toch·tho·nous/ (aw-tok´thah-nus) 1. originating in the same area in which it is found. 2. denoting a tissue graft to a new site on the same individual. in surveyed sites, although highly heterogeneous between sites. Observed childhood-acquired immunity indicates that not all cases are imported from Afghanistan, as has been suggested (5). Consequently, continual and vigilant surveillance is required to monitor the epidemiology of ACL in the region. The mass return of Leishmania-infected refugees to urban areas in Afghanistan poses a particular risk, since housing is often poor, and living conditions living conditions npl → condiciones fpl de vida living conditions npl → conditions fpl de vie living conditions living are crowded. Including ACL prevention measures in Afghanistan's basic package of health services health services Managed care The benefits covered under a health contract (e.g., supplying insecticide-treated nets to areas at high risk) should be considered to prevent the spread of disease through previously ACL-free urban areas. Current ACL interventions in the study areas in Pakistan are funded by the United Nations High Commissioner for Refugees Headquartered in Geneva, Switzerland, the Office of the UN High Commissioner for Refugees (UNHCR) (established December 14, 1950) protects and supports refugees at the request of a government or the United Nations and assists in their return or resettlement. (UNHCR UNHCR n abbr (= United Nations High Commission for Refugees) → ACNUR m UNHCR n abbr (= United Nations High Commission for Refugees) → HCR m ) and mainly focus on Afghan refugees. Free diagnosis on the basis of clinical symptoms, analysis of specimens by microscope, and treatment with antimony antimony (ăn`tĭmō'nē) [Lat. antimoneum], semimetallic chemical element; symbol Sb [Lat. stibium,=a mark]; at. no. 51; at. wt. 121.75; m.p. 630.74°C;; b.p. 1,750°C;; sp. gr. (metallic form) 6. are provided for all patients attending basic health units in refugee camps, and insecticide-treated nets are sold at highly subsidized prices to refugees with active ACL. The local population is not a focus of the program, since resources are limited. Insecticide-treated net users in local villages either make their own nets or acquire them through "leakage" of nets intended for Afghan refugees or at communities across the border in Afghanistan. Long-term control of ACL transmission in Pakistan will require extending diagnostic and treatment services and building up a program to sell insecticide-treated nets to the local population. With the ongoing reduction in UNHCR funding and anticipated phasing-out of support to refugee health care at the end of 2005, the population will depend on the Pakistan Ministry of Health to deliver these much needed services.
Table 1. Unadjusted odds ratios for variables associated with the risk
of anthroponotic cutaneous leishmaniasis lesion and scar (a)
Variable Lesion [OR (95% CI)]
Village (b) [chi square] = 540,
df = 66, p < 0.001
Refugee camp (compared to local
village) 1.540 (1.16-2.06), p = 0.003
Nationality (Afghan compared to
Pakistani) 1.050 (0.78-1.38), p = 0.720
Years lived in camp/village 1.010 (1.01-1.02), p < 0.001
Family member visited Afghanistan in
last 12 mo. 1.740 (1.37-2.20), p < 0.001
Lesion prevalence in other household
members 1.120 (1.11-1.13), p < 0.001
Scar prevalence in other household
members 1.030 (1.02-1.03), p < 0.001
Sex (female compared to male) 1.010 (0.89-1.15), p = 0.770
Age group (compared to 0-4 y)
5-19 y 1.090 (0.87-1.37), p = 0.450
[greater than or equal to] 20 y 0.560 (0.43-0.71), p < 0.001
Type of wall (compared to mud)
Brick 0.940 (0.33-2.68), p = 0.920
Stone 0.530 (0.32-0.88), p = 0.010
Other 2,000 (0.76-5.21), p = 0.150
Type of ceiling (compared to cloth)
Concrete 0.690 (0.26-1.79), p = 0.450
Wood (beam) 1.430 (0.65-3.17), p = 0.370
Wood (thatched) 0.460 (0.16-1.27), p = 0.140
Other 0.850 (0.30-2,41), p = 0.760
Rooms/person 0.200 (0.07-0.56), p = 0.002
Cows in compound (yes/no) 1.420 (1.22-1.65), p < 0.001
Dogs (yes/no) 1.660 (1.42-1.94), p < 0.001
Meshed windows (% windows covered) 1.260 (0.51-3.13), p = 0,610
Use mosquito net 1.180 (0.83-1.67), p = 0.350
Treated mosquito net 0.760 (0.32-1.78), p = 0.530
Variable Scar [OR (95% CI)]
Village (b) [chi square] = 786,
df = 66, p < 0.001
Refugee camp (compared to local
village) 0.82 (0.62-1.09), p = 19
Nationality (Afghan compared to
Pakistani) 0.940 (0.70-1.26), p = 0.680
Years lived in camp/village 1.002 (0.99-1.01), p = 0.510
Family member visited Afghanistan in
last 12 mo. 1.690 (1.35-2.11), p < 0.001
Lesion prevalence in other household
members 1.040 (1.03-1.06), p < 0.001
Scar prevalence in other household
members 1.090 (1.08-1.10), p < 0.001
Sex (female compared to male) 1.050 (0.95-1.16), p = 0.310
Age group (compared to 0-4 y)
5-19 y 1.750 (1.44-2.13), p < 0.001
[greater than or equal to] 20 y 1.080 (1.07-1.59), p = 0.007
Type of wall (compared to mud)
Brick 0.640 (0.31-1.31), p = 0.220
Stone 0.480 (0.30-0.77), p = 0,002
Other 1.160 (0.59-2.31), p = 0.650
Type of ceiling (compared to cloth)
Concrete 1.090 (0.44-2,71), p = 0.850
Wood (beam) 1.590 (0.73-3.48), p = 0.240
Wood (thatched) 1.770 (0.70-4.49), p = 0.230
Other 1.180 (0.47-2.99), p = 0.710
Rooms/person 0.430 (0.21-0.91), p = 0.020
Cows in compound (yes/no) 1.510 (1.34-1.69), p < 0.001
Dogs (yes/no) 1.310 (1.16-1.48), p < 0.001
Meshed windows (% windows covered) 0.720 (0.32-1.61), p = 0.420
Use mosquito net 1.560 (1.19-2.05), p = 0.001
Treated mosquito net 0.740 (0.42-1.32), p = 0.320
(a) OR, odds ratio; CI, confidence interval; df, degrees of freedom.
(b) The overall significance of this categorical variable is shown
rather than the 67 different survey locations.
Table 2. Adjusted odds ratios associated with risk of anthroponotic
cutaneous leishmaniasis lesion and scar, based on multiple logistic
regression model, using village as a random effect variable
Variable Adjusted OR (95% CI) (a)
Lesion
Age group (compared to 0-4 y)
5-19 y 1.17 (0.90-1.52) p = 0.320
[greater than or equal to] 20 y 0.48 (0.35-0.65) p < 0.001
Lesion prevalence in other household
members 1.10 (1.09-1.11) p < 0.001
Scar
Age group (compared to 0-4 y)
5-19 y 2.52 (1.93-3.29) p < 0.001
[greater than or equal to] 20 y 1.99 (1.48-2.69) p < 0.001
Refugee camp (compared to local village) 1.48 (1.03-2.14) p = 0.040
Scar prevalence in other household
members 1.08 (1.07-1.11) p < 0.001
(a) OR, odds ratio; CI, confidence interval.
Acknowledgments We are grateful to the HealthNet International survey team and the temporary surveyors for collecting data and Clive Davies and Paul Coleman for statistical advice and comments on the manuscript. The HealthNet International Malaria and Leishmaniasis Control Programme in Pakistan is supported by the UNHCR, who does not accept responsibility for the information provided or views expressed. S.B. is supported by the Wellcome Trust The Wellcome Trust is a United Kingdom-based charity established in 1936 to administer the fortune of the American-born pharmaceutical magnate Sir Henry Wellcome. Its income was derived from what was originally called Burroughs Wellcome & Co, later renamed in the UK as the . References (1.) Nadim A, Javadian E, Noushin MK, Nayh AK. Epidemiology of cutaneous leishmaniasis cutaneous leishmaniasis n. An endemic disease in northern Africa and western and central Asia, caused by infection with promastigotes of Leishmania tropica and transmitted by the bite of a sandfly of the genus Phlebotomus. in Afghanistan. 11. Anthroponotic cutaneous leishmaniasis. Bull Soc Pathol Exot Filiales. 1979;72:461-6. (2.) Reyburn H, Rowland M, Mohsen M, Khan B, Davies C. The prolonged epidemic of anthroponotic leishmaniasis in Kabul, Afghanistan: 'bringing down the neighbourhood'. Trans R Soc Trop Med Hyg. 2003;97:170-6. (3.) Reithinger R, Mohsen M, Aadil K, Sidiqi M, Erasmus P, Coleman PG. Anthroponotic cutaneous leishmaniasis, Kabul, Afghanistan. Emerg Infect Dis. 2003;9:727-9. (4.) Massoom M, Marri SM. Current status of leishmaniasis in Pakistan. In: Bhaduri AN, Basu MK, Sen AK, Kumar S Kumar (from Sanskrit meaning prince or an (unmarried) youth) is an Indian title, given name or family name. As a title it can mean son of a Rājā, prince, or heir apparent and enters in princely compound titles. , editors. Current trends in Leishmania research. Calcutta, India: Council of Scientific and Industrial Research The Council of Scientific & Industrial Research (CSIR) is the premier industrial research and development (R&D) organization in India. It was founded on 26 September, 1942, by a resolution of the then Central Legislative Assembly. ; 1993. p. 231-6. (5.) Rowland M, Munir A, Durrani N, Noyes H, Reyburn H. An outbreak of cutaneous leishmaniasis in an Afghan refugee settlement in northwest Pakistan. Trans R Soc Trop Med Hyg. 1999;93:133-6. (6.) Kolacziaski J, Brooker S Brooker may refer to:
(7.) Williams B, Dye C. Maximum likelihood methods for parasitologists. Parasitol Today. 1994;10:489-93. (8.) Lysenko AJ. Beljaev. Quantitative approaches to epidemiology. In: Peters W, Killick-Kendrick R, editors. The leishmaniases in biology and medicine. Volume 1. London: Academic Press; 1987. p. 263-90. (9.) Dereure J, Rioux JA, Gallego M, Perieres J, Pratlong F, Mahjour J, et al. Leishmania tropica in Morocco: infection in dogs. Trans R Soc Trop Med Hyg. 1991 ;85:595. (10.) Nasir AS. Sandflies as a vector of human disease in Pakistan. Pakistan J Health. 1964;14:26-30. Dr. Brooker is an infectious disease Infectious disease A pathological condition spread among biological species. Infectious diseases, although varied in their effects, are always associated with viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. epidemiologist at the London School of Hygiene and Tropical Medicine tropical medicine, study, diagnosis, treatment, and prevention of certain diseases prevalent in the tropics. The warmth and humidity of the tropics and the often unsanitary conditions under which so many people in those areas live contribute to the development and . His research interests are the epidemiology and control of infectious diseases infectious diseases: see communicable diseases. . Simon Brooker, * Nasir Mohammed, ([dager]) Khaksar Adil, ([dagger]) Said Agha, ([dagger]) Richard Reithinger, * ([dagger] Mark Rowland Mark Rowland (born March 7 1963 in Watersfield, West Sussex, England) was a British athlete who was a shock medallist at the 1988 Summer Olympics in Seoul. Unheralded and unknown both in his own country and globally prior to the Games, the tall and ungainly Rowland came , * Iftikhar Ali, ([dagger]) and Jan Kolaczinski * ([dagger]) * London School of Hygiene and Tropical Medicine, London, United Kingdom: and ([dagger]) HealthNet International, Peshawar, Pakistan Address for correspondence: Jan Kolaczinski, Disease Control and Vector Biology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom; fax: +44-(0)-20-7927-2918; email: jan.kolaczinski@lshtm.ac.uk |
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