Cutaneous Leishmaniasis Analyses in an Endemic Focus in Southwest Iran (2016-2020)

Background : The cutaneous type of leishmaniasis (CL) has widespread growth. This research was conducted to explore the epidemiological characteristics of CL in the county of Shush in the Khuzestan Province located in the southwestern region of Iran. Methods: This cross-sectional study was retrospectively conducted from 2016 to 2020. Patients’ demographics and medical history were acquired to some extent. The recorded data of patients with CL referred to Shush health centers were analyzed using the SPSS software (Chicago, IL). Results: Overall, 2020 patients were recorded from 2016 to 2020. Among Shush residents, the incidence of CL ranged from 126.2 to 285.8 cases per 100 000 people. The results demonstrated a statistically significant difference in the number of people who got CL in Shush county ( P < 0.05). Based on the results, a statistically significant correlation was found between CL and gender (including 54.7% males against 45.3% females, P < 0.05). CL was found in more significant numbers in the age groups under ten years old (42.6%) compared to the other age groups ( P < 0.05). Conclusion: Shush seems to be a CL endemic hotspot based on the results of this research and other epidemiological parameters. The intensity of CL reports from this study and other epidemiological studies suggests that CL is more prevalent in Shush than in previous. The situation is extremely alarming; thus, it is highly recommended that adequate measures be taken to control and prevent the spread of illness.

does not threaten their lives (3,8,9). Leishmania species and the host's immunological response determine the infection period (acute to long-term) and its severity (6). Approximately 20 distinct Leishmania parasite species are responsible for leishmaniasis across the globe (10,11).
It is transmitted from an animal to a person by biting an infected female phlebotomine sand fly with leishmaniasis (7). Most disease transmission cycles on the planet are caused by zoonoses, including reservoir hosts such as mice, monkeys, domestic dogs, and wild canids, as well as humans (7,12). Sand flies may transmit a parasite that may effectively move from human-to-human hosts but does not need a reservoir for leishmaniasis, which may be anthroponotic (7). Overall, fewer than 100 species of sand flies out of roughly 1000 species have been identified as the vectors of the Leishmania parasite (13).
There is a link between the frequency of leishmaniasis and changes in environmental factors, including deforestation, dam building, agricultural initiatives, Dis Diagn. Vol 11, No 4, 2022 138 http://ddj.hums.ac.ir http and urban growth, among others (2). Numerous more factors affect those who live in poverty, including hunger, population shifts, insufficient infrastructure, weakened immune systems, and an absence of financial resources (2). Iran reports around 20 000 CL cases every year, according to one study, but the researchers believe the accurate figure is four to five times greater (9,14). In earlier research, CL was classified into zoonotic (caused by Leishmania major) and anthroponotic (caused by Leishmania tropica) types, as well as wet and dry lesions in Iran's rural and urban regions, respectively (14,15). Phlebotomus papatasi, P. duboscqi, P. salehi, and P. caucasicus are all the vectors of zoonotic (ZCL) in Iran (16). ZCL has been reported to be prevalent in 17 provinces of Iran, including Khuzestan province, where ZCL may be found in a wide range of locations (17). Throughout the province of Khuzestan, the L. major is the most abundant and vital CL species (18,19).
The purpose of this study was to investigate the epidemiology parameters of this illness in Shush County from 2016 to 2020. It is required to undertake an epidemiological study to establish if the present interventions in Shush County would be successful against a causative CL strain; preliminary information on the illness was obtained and evaluated accordingly.

Materials and Methods
Shush county (48º 24' E, 32º 19' N) is situated in Khuzestan province, southwest Iran, at 87 m above sea level ( Figure 1). It has an area of 3557 km 2 with a hot and arid environment. Many individuals work in agricultural and animal production in this area (20).
The incidence of CL was obtained from a retrospective study conducted on 2020 instances of CL reported to the Shush county health centers between 2016 and 2020. Some unique patient variables such as age, gender, occupation, and year (or years) were recorded based on the study purpose. Using the chi-square statistics test, an analysis was performed on the obtained data to find whether there were any relationships between the epidemiological parameters and the frequency of CL. The data were then analyzed by the SPSS software, version 26 (Chicago, IL).

Results
A total of 2020 cases of CL were reported between 2016 and 2020, with monthly distribution (Figure 2). The highest and lowest percentages of people who had the illness were 32% in 2020 and 13.5% in 2019, respectively. The incidence rate per 100 000 people statistically significantly differed across the several research years according to the chi-square goodness-of-fit test (P < 0.05). The disease's yearly incidence peaked at 285.8 cases per 100 000 people in 2020, while its lowest rate was 126.2 cases per 100 000 people in 2019 (Table 1).
Females and males made up 45.3% and 54.7% of the patients, respectively. A chi-square goodness-offit statistic test was used to determine whether CL is differently distributed in terms of gender. Males and females significantly differed in the frequency with which they used CL (P < 0.05). Regarding the number of infected persons with CL, the results indicated that CL was not the same in both genders. Based on a chi-square goodness-of-fit test, CL seems to have the highest frequency among under ten-year-olds (42.6%), while the lowest frequency was related to the age group of 50-59 years old (2.9%).
To evaluate whether the age of those infected patients with CL differs from chance, a statistically significant disparity was found in the number of persons infected with CL (P < 0.05). More than half (61.0%) of those surveyed were under 20 ( Table 2). The youngest and oldest patients were 1 and 97 years old. Children were shown to have the most significant condition incidence (32.8%).
It was determined if the frequency of infected patients with CL in the 11 categories of jobs varies from chance using the chi-square goodness-of-fit test. There was a statistically significant difference in the frequency of infected patients with CL between the eleven groups related to the occupation (P < 0.05).

Discussion
Following malaria, leishmaniasis, a neglected tropical disease, is responsible for most impairments among parasite illnesses (21).
A total of 2020 confirmed cases of CL were found during 2016-2020. It seems that CL has had a surge in the number of years it has been under investigation.
Both men and women of all ages were afflicted with CL; however, it was more prevalent in men (54.7%) than women (54.3%). Similar findings have been published throughout the country and worldwide (9,14,(22)(23)(24)(25)(26). Men are more likely to get sand fly bites than women because they wear fewer garments and participate in more outside activities such as sports and night employment, which exposes them to more sand fly bites (9,23,24). Conversely, the results of a study conducted in southern France represented that CL had a similar effect on men and women (27).
Soldiers, miners, cops, and loggers are most at risk for contracting CL (24,28). Among youngsters, a phenomenal rate (32.8%) was observed in the occupational groupings according to our findings. We found that our results followed the outcomes of the studies that have been conducted in the other regions of Iran (9,14,26). According to the research, both males and females under the age of 10 (42.6%) include female group which is most significantly influenced by the disease. It may also be ascribed to the greater likelihood of being bitten by a sand fly when participating in outdoor activities. Interestingly, the findings of this research are consistent with those of other investigations by Omidieh and Aran-va-Bidgol (9,26). However, similar findings were not reported in the other areas of Iran or other parts of this Province (23,25,29,30).
CL affected 61.2% of people who lived in rural areas, and the difference between the different residencies was significant.
The analysis findings revealed that CL happened more during the winter months than during the other seasons ( Figure 2).
Based on the evidence, the number of people infected with CL illness is increasing in Iran and other parts of the globe (9). It was shown that the CL incidence was the lowest in 2019, while its highest frequency was observed in 2020 (per 100 000 people). In Shush County, we found an incidence rate of 182.4 per 100 000 people compared to the national average of 27.5 (14). As a result, the prevalence of CL in Shush was far greater than predicted, whereas the prevalence of CL across Iran was significantly lower. CL may be an endemic illness in this county, or the disease's incidence may be growing due to the lack of the implementation of numerous critical tasks in the CL program, including reservoir and vector control, as well as early identification and treatment.
In light of these findings, public health education and management of the illness, reservoirs, and vectors in the Shush area may effectively eradicate CL in the human population.

Conclusion
According to the findings of this research, Shush seems    to be a significant endemic focus for CL in the country. As a result, to defeat the illness, implementing control programs such as vector and reservoir management, as well as raising people's knowledge of personal protective techniques, should be resurrected in the area to combat the disease.