1. Background
Leishmaniasis is caused by a parasite from a protozoan family, which occurs in three forms: cutaneous, cutaneous-mucosal, and visceral. The infection is transmitted to humans and other mammals, mainly by being bitten by an infected sandfly (1). The Cutaneous form of leishmaniasis starts with a small bump (papules), which gradually enlarges and turns into scares likely to heal on their own in weeks or months, and sometimes years, imposes a heavy economic burden on society, especially in developing countries (2). Cutaneous leishmaniasis is categorized as either rural (Zoonotic leishmaniasis as wet leishmaniasis or premature leishmaniasis), with rapid growth but mild symptoms caused by Leishmania major, or urban (Anthroponotic leishmaniasis as late-onset dry or injured leishmaniasis), with a more prolonged course by Leishmania tropica (3, 4). In most cases, patients develop immunity by the natural course of the disease, and the infection is eliminated with a defined scare. Despite no complete elimination of the infection, treatment accelerates the healing process but with a compromised immunity response (5, 6). All patients with urban cutaneous leishmaniasis (ACL), which patients transmit, should be treated to prevent the spread of the disease. However, in rural leishmaniasis (ZCL), covering the wound to prevent flies from access to the contagious wound is very important and sufficient to prevent the infection’s spread. The therapeutic goals of CL are: (i) 100% recovery of patients, (ii) prevention of lesion spread mainly in the face, (iii) control of the disease reservoirs, and iv) prevention of complications such as secondary infection, lymphangitis, and prevention of disease recurrence (7). The social stigma caused by the scares causes many psychological problems in the patients. For example, people with CL scares encounter social limitations in Afghanistan and Colombia (8, 9). World Health Organization has announced the family of leishmaniasis infections as one of the six most important tropical and semi-tropical infections worldwide (10, 11). Based on the reports, leishmaniasis is endemic in 98 countries (12). In addition, it is estimated that about 350 million people are at risk of catching the infection, causing 70,000 deaths (13). About 90% of the world's cutaneous leishmaniasis (CL) is reported in Afghanistan, Brazil, Iran, Peru, Saudi Arabia, and Syria (14). About 30,000 new cases are reported annually in Iran, which is considered times more significant (15). Marvdasht is one of the foci of Leishmania in Iran. This is the first study in Iran that simultaneously examines active and old scars in the population to investigate people at risk of contracting the disease in the future and the possibility of epidemics and pandemics.
2. Objectives
This study aims to estimate the lifetime and point prevalence of CL in the general population of the Fars province.
3. Methods
Assuming the presence of CL active and old scars indicates the present and past (lifetime) infections. This study was conducted to investigate the epidemiology of CL in 2019. Accordingly, a cross-sectional study was performed in the county to measure CL’s point and lifetime prevalence among the population.
Marvdasht County is 1620 m above sea level with 4649 km2, located in the North of Fars province, Iran. Based on the 2011 census in Iran, the county has a population of 137,087 whose occupation is mainly agriculture and food industry (16, 17).
3.1. Data Collection
3.2. Sampling
A two-stage systematic random and cluster sampling was carried out to select 59 urban and 55 rural clusters (based on the rural and urban population) from a list of all urban and rural households covered by Marvdasht health center (covering more than 95% of the population). Each cluster was selected randomly within a list of all rural or urban households registered with the health cancer as a cluster’s starting point, which included 30 neighboring households on the right of the cluster starting point. The sampling interval was identified by dividing the number of households (in urban and rural areas) by the defined number of clusters.
3.3. Statistical Analysis
Descriptive statistics (mean and percentage) were used to summarize the data. Chi-square was used to compare quantitative and qualitative variables distribution among the comparing groups. SPSS software Version 16 was used to analyze the data. The difference is considered statistically significant if P < 0.05.
4. Results
A total of 3258 households, including 1608 urban and 1650 rural, were visited in this study, and 11,779 individuals were included. The results showed that the point prevalence of CL was 3.56 (2.6 - 4.8) per 1000 population (42 individuals with active scars). In addition, the lifetime prevalence among the study population was 8.48% (7.99 - 9) (998 individuals with old scars) (Table 1).
Table 1.Point and Lifetime Prevalence of Cutaneous Leishmaniasis in Marvdasht, Fars Province Iran, 2019
| Variables | Total | Male | Female |
|---|---|---|---|
| Point prevalence (active scar) | 0.35 (0.26 - 0.48) | 0.37 (0.23 - 0.55) | 0.27 (0.15 - 0.45) |
| Lifetime prevalence (old scar) | 8.48 (7.99 - 9) | 8.31 (7.64 - 9.02) | 7.61 (6.91 - 8.34) |
A total of 0.36% and 8.30% of patients with active or old CL scars were males, respectively. On average, those with active or old scars were 36.05 ± 21.10 and 35.59 ± 19.34 years old, respectively. The highest prevalence of active and old CL scars was among those in 2 - 40 years. The lowest prevalence of active and old scars was among those under-five years of age, and 38.37% of patients with CL scare were housewives and jobless (Table 2).
Table 2.Distribution of CL Scar by Age and Job Participants in Marvdasht, Fars Province, Iran a
| Variables | Population | With CL Active Scare | With CL Old Scare |
|---|---|---|---|
| Age, y (mean ± SD) | 35.79 ± 20.14 | 36.0 ± 21.1 | 35.59 ± 19.34 |
| < 5 | 1178 (9.9) | 3 (0.25) | 32 (2.71) |
| Between 6 and 20 | 2443 (20.47) | 7 (0.28) | 197 (8.06) |
| Between 21 and 40 | 5803 (49.26) | 24 (0.41) | 661 (11.39) |
| > 41 | 2355 (19.99) | 7 (0.29) | 108 (4.58) |
| P-value | - | 0.69 | 0.0001 |
| Job | |||
| Housekeeper/jobless | 4716 (40.03) | 19 (0.40) | 383 (8.21) |
| Private job/clerk | 2952 (25.06) | 7 (023) | 75 (2.5) |
| Student/soldier | 1179 (9.99) | 5 (0.46) | 176 (14.92) |
| Farmer/rancher | 1435 (12.18) | 9 (0.62) | 80 (5.57) |
| < 7 years | 1497 (12.7) | 2 (0.13) | 40 (2.67) |
| P-value | - | 0.15 | 0.0001 |
a Values are expressed as No. (%) unless otherwise indicated.
There was no difference between urban and rural areas and gender in terms of fresh or old scars, and CL scares (P ≥ 0.05 for all) (Table 3). The most commonly used method for preventing CL was using more than one method (64.91%) (2115 people) to prevent mosquito bites (Table 4).
Table 3.Distribution of CL Scar by Gender and Residency of the Included Individuals in Marvdasht, Fars Province, Iran, 2019
a Household base.
Table 4.Distribution by Insect Bite Protection Tool of Participants in Marvdasht, Fars Province, Iran, 2019
| Variables | No. (%) |
|---|---|
| Used protection instrumentation a | |
| Mosquito net | 309 (9.48) |
| Lace | 477 (14.64) |
| Insect repellent pen | 12 (0.36) |
| Clothes | 140 (4.29) |
| No protection | 205 (6.29) |
| More than one protection tool | 2115 (64.91) |
a Household base.
5. Discussion
The present study investigated CL’s point and lifetime prevalence in the general population of Mardusht in 2019. CL prevalence was 3.56 per 1000, and the lifetime prevalence was 8.5 per 100.
According to Asadi et al., the lifetime prevalence of CL was estimated at 15.4 per 100,000 in Fars Province (20), which was lower than the same figure in Marvdasht. In addition, the lifetime prevalence was 20.32 and 25.93 in men and women, respectively. The prevalence of CL (lifetime and the current prevalence) was higher in men than women, which is consistent with the same results obtained for Iran (21-23).
The average age of actives scar was 36.05 for people with leishmaniasis; old scars were 35.59. Most of the frequency of active and old scars was in the age group of 21 to 40 years. In Almasi-Hashiani et al.'s study, the most reported cases were 15-30 years old (24). In Khajedaluee et al., the prevalence of the disease by age group was in the age group ≥ 10 years, and the lowest was in the age group more than 61 years (25).
This study revealed that the lowest frequency of people with leishmaniasis (active and old scar) was related to the age group of fewer than five years. In Khosravani Poor et al., the highest prevalence of the disease was found in the age group below ten years old. In the present study, 3.63% of the people had an active lesion, and the highest frequency of the infection (21.91%) was found in the age group of 0 - 4 years (21).
In this study, only 9.8% of the households use mosquito nets, probably due to low income. This result is consistent with that of Khosravani Poor et al.'s study, which showed that a small percentage of households use mosquito nets (21). In general, the use of personal protective equipment in this study was high, while this rate was low in Heshmati et al. in Yazd (26).
5.1. Limitations
This study was cross-sectional, and it was impossible to investigate the relationship between fresh wounds and related factors.
5.2. Conclusions
Marvdasht is one of the important centers with high pollution in Fars province. Based on the results, about 90% of the population of Marvdasht is not safe from this disease with the high frequency of active scares in the area, and they are prone to infection. Therefore, CL is a severe health problem, and an epidemic is probable to occur in the area.
