An eco-epidemiological
study of cutaneous leishmaniasis in Dezful, Iran, during 2004-2011
Hashemi H, PhD 1,
Khodabakhshi A, PhD2, Sepasian M, MSc 3*
1. Assistant Prof.,
Research Center for Health Sciences, Shiraz University of Medical Sciences,
Shiraz, Iran. 2. Assistant Prof., Health Faculty, Shahrekord University of
Medical Sciences, Shahrekord, Iran. 3. MSc of Medical Geography, Faculty of
Geographical Sciences and Planning, University of Isfahan, Isfahan, Iran.
Abstract
Received: July 2015, Accepted: August 2
015
|
Background: Due to annual increases in cutaneous leishmaniasis (CL) in
different regions of Iran and the resulting health problems and high economic
costs, this study was performed with the aim to determine the prevalence of
CL in Dezful city, Iran. Materials and Methods: This descriptive study was performed on all patients who were
directly referred to clinics and clinical laboratories of Dezful city during
2004-2011. Age, sex, occupation, and area of residence of the patients were
recorded. Biopsy was conducted on
patients who had suspicious lesions. The biopsy was evaluated by a
parasitologist using Giemsa staining, and then, light microscopy. Results:
The number of CL cases was 1192, among which 64% were men and 36% were women.
Among them, 592 people lived in rural areas and 600 people lived in urban
areas. Most cases of disease were in the age group of 20-29 years (35%). The
maximum prevalence of disease was observed in 2008. Most cases of the disease
were in the military occupational group with a frequency of 366 cases.
Furthermore, most cases occured in the months of November and December. Conclusions: Considering the prevalence of CL
in the study area in different years, it is necessary to take effective and
comprehensive public health measures to control and prevent the spread of
this disease. |
Keywords: Cutaneous
leishmaniasis, Epidemiology, Iran.
Introduction
Leishmaniasis is a zoonotic
infection in which parasites of the genus leishmania are transmitted from
rodents and small mammals to phlebotomus species and fly vectors. Humans may
inadvertently enter the zoonotic cycle and contract cutaneous
leishmaniasis (CL) (1, 2). It is caused by an obligate intramacrophage
protozoan, characterized by diversity and complexity (3). The different
clinical forms of leishmaniasis cause severe public health problems. Visceral
leishmaniasis (VL) is usually fatal when untreated, muco-cutaneous
leishmaniasis (MCL) is a mutilating disease, diffuse cutaneous leishmaniasis
(DCL) is a disabling disease, and cutaneous leishmaniasis (CL) is also
disabling when multiple lesions are present (4, 5). In temperate areas of the
Old World, there is a seasonal appearance of sandflies. There are two peaks in
the density curve of most species; one in June or July and the other in August
or September (6). This disease manifests as a chronic ulcer, potentially
leaving unattractive*scars (7). CL
is a worldwide public health and social problem in many developing countries.
It can affect the skin and mucous membranes, and is caused by different
Leishmania species widespread in 88 countries in the New and Old World. Old
World CL is present in many endemic areas in North Africa, the Mediterranean,
the Middle East, the Indian subcontinent, and Central Asia. The World Health
Organization (WHO) considers leishmaniasis to be one of the most serious
parasitic diseases and the World Health Assembly (WHA) has advocated
conservation for its control (8). The overall prevalence of CL is 12 million
with an estimated 1.5 million new cases of CL per year. Approximately 350
million people, who are often impoverished, are at risk of contracting the
disease (9).
Old World CL is also increasingly
seen in immigrants, military personnel, humanitarian aid workers, tourists, and
travelers from endemic areas. However, imported CL is still missed by most
western physicians. Suspected skin lesions must be analyzed through biopsies
and tissue smears in order to make an accurate diagnosis (10). Dezful city in
the North of Khuzestan Province, Iran, is an endemic area of CL. Thus, this
study was performed with the aim to determine the prevalence of CL and its
characteristics in patients who were referred to health centers in Dezful due
to skin problems. The study results can be effective in treatment of infected individuals, prevention of infection
prevalence in the society, and health centers’ short-term and long-term
planning for disease prevention and control.
Material
and methods
This descriptive study was conducted over a period of 8 years
from April 2004 to 2011 in the clinical laboratories of Dezful using
convenience sampling. All patients referred to clinical laboratories of health
centers in towns and villages around Dezful and in the city of Dezful and
diagnosed with leishmaniasis due to injury were investigated. The data on these
patients was recorded in the health center within the city and under the
supervision of Dezful University of Medical Sciences.
Sampling was carried out and samples with Giemsa staining and
microscopy were examined by a parasitologist. Then, questionnaires were completed for patients with CL. The
questions obtained information on age, sex, occupation,
place of residence, and the number and location of lesions.
In this study, patients with CL were those who had amastigote
forms in the leishmania antigen mixture (LAM) prepared for them. Data were
collected and classified and graphs were prepared using Excel software.
Table 1: The number
of patients with cutaneous leishmaniasis (CL) based on months and years in
Dezful
|
Month Year |
Janary |
February |
March |
April |
May |
June |
July |
August |
September |
October |
November |
December |
Total |
|||||
|
2004 |
16 |
1 |
4 |
8 |
7 |
6 |
2 |
9 |
10 |
15 |
37 |
41 |
156 |
||||
|
2005 |
43 |
28 |
12 |
2 |
4 |
1 |
4 |
7 |
15 |
26 |
25 |
40 |
207 |
||||
|
2006 |
16 |
8 |
12 |
16 |
2 |
5 |
5 |
3 |
8 |
11 |
21 |
22 |
129 |
||||
|
2007 |
25 |
7 |
3 |
7 |
5 |
2 |
2 |
2 |
2 |
7 |
7 |
23 |
92 |
||||
|
2008 |
52 |
33 |
15 |
3 |
0 |
4 |
0 |
9 |
23 |
18 |
43 |
54 |
254 |
||||
|
2009 |
11 |
9 |
3 |
10 |
3 |
3 |
2 |
13 |
19 |
13 |
20 |
11 |
117 |
||||
|
2010 |
6 |
2 |
1 |
2 |
1 |
1 |
4 |
12 |
6 |
12 |
21 |
15 |
83 |
||||
|
2011 |
7 |
7 |
14 |
2 |
0 |
3 |
3 |
10 |
12 |
37 |
36 |
23 |
154 |
||||
Results
According to data recorded by the Dezful City Health Center,
1192 cases of this disease were observed during the years 2004-2011 (Table 1), 767 of which (64%) were men and 425 (36%) women (Figure 1). Among them, 592 patients lived in rural areas
and 600 patients lived in urban
areas. Most cases
were observed in 2008.
Figure 1: Cases of cutaneous leishmaniasis (CL) in Dezful during the study
period
In this study, patients with CL are grouped in terms of age. Thus,
most of the cases (35%) were in the age group of 20-29
years (Table 2). According to figure 2, most of the
people in this region who suffer from this disease have been in the military. The city has several military garrisons that the data showed to be endemic areas of CL during 2004-2011. This finding is
justifiable as the people in these garrisons were mostly nonnatives. The
garrison building environment is suitable for the growth and multiplication
of vectors of CL, because sandflies generally live in
wall cracks and wet and warm places.
After military personnel, housewives
and students, respectively, were the groups with the highest number of cases of
this disease. Moreover, 163 children and babies who could not be entered into
occupation or education classifications had this disease. It should be
mentioned that the “other jobs” group included
56 self-employed, 17 unemployed, and 9 employed
individuals (Figure 2).
Table 2: Age distribution
of cutaneous leishmaniasis (CL) cases in Dezful during the study period
|
Age group |
0-9 |
10-19 |
20-29 |
30-39 |
40-49 |
50-59 |
60+ |
|
Number of cases |
261 |
281 |
414 |
101 |
66 |
34 |
35 |
|
Percentage |
22% |
24% |
35% |
8% |
5% |
3% |
3% |
Figure
2: Occupational distribution of cutaneous leishmaniasis (CL) cases in Dezful
during the study period
The obtained data show that most cases of disease occurred in
autumn. In fact, few CL cases were observed in the first months of the year,
and most cases were observed in October, November,
December, January, and February. The peak was in December and
November (Figure 3).
Figure
3. The average number of cutaneous leishmaniasis (CL) cases per month in the
city of Dezful
Discussion
CL is expressed as a myriad of disease manifestations which
depend upon parasite species, host responses, and poorly understood
host-parasite-vector interactions. Several species of Leishmania are capable of
infecting humans and causing disease (8). Leishmaniasis is endemic in 88
countries in the world, and 350 million individuals are at risk of acquiring
the disease (2). Although CL is not life threatening, it can cause morbidity due to numerous reasons
such as long duration of ulcers, high cost of treatment, length of the
treatment period, and side effects of
treatment with existing drugs (3).
In this study, the prevalence of leishmaniasis in Dezful was 64%
in men and 36% women. According to previous studies, this difference can be due
to the different occupational positions of men and women and difference in clothing which in women is more than men.
In addition, most cases counted for low elevation areas and the least number of
cases for high elevations areas (5-7).
Dezful is one of the endemic areas of CL.
The high prevalence of this disease in this region can be attribute to the low
elevation, gardens, agriculture, plant covering, and soil texture of the region
that create the right environment for the growth of the disease reservoirs. An
increase in the number of rats that are one of the main reservoirs of CL can
also be observed around Dez River. On the other hand, climate factors such as
humidity, rainfall, sunshine, temperature, and wind are also contributing
factors to the spread of disease vectors in this region.
As data has shown, most cases (35%) were in
the 20-29 years age group and many of them were soldiers. This may indicate the
greater exposure of this group (Table 2). The obtained data showed a CL epidemic in garrisons in Dezful during 2004-2011. This
finding is justifiable as the people in these garrisons were mostly nonnatives. . On the other hands, nonnatives who travel to this area
are a reason for the spread of CL to other areas and neighboring provinces.
After military personnel, housewives and students, respectively, were the
groups with the highest number of cases of this disease
because these groups were exposed to fly bites.
The findings also indicated that
leishmaniasis was most prevalent in November and December of every year and this
is due to the existence of dominant species (leishmania
major) in the region. During the study period, highest rate of disease cases
was in 2008 and the lowest rate in 2010 (Table 1). The reduction or increase in
the number of cases of disease can be attributed to occurrence of naturally acquired immunity in people who were formerly infected
with leishmania. For example, there was an epidemic among soldiers in 2008 and
the number of disease cases increased; this may have been due to the
susceptibility of nonnatives to the disease parasite compared to native
residents.
Conclusions
Although Dezful has been recognized as an endemic
area of CL,
no scientific research has been carried out in this region. The
results of this study show that the CL is acquired every year and spreads to
other non-endemic regions. In order to prevent
the spreading of CL, more epidemiological studies
and the establishment of many surveillance and control systems are required.
Acknowledgement
The
authors would like to acknowledge the generosity of workers who agreed to
participate in this research.
Conflict
of interest: Non declared
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* Corresponding author: Mahsa Sepasian, Faculty of Geographical Sciences and Planning, University of
Isfahan, Isfahan, Iran.
Email: chitra_tetra@yahoo.com