Non-Iranian travelers may threaten malaria elimination in Iran

Shahrzad Soltani, Masoud Foroutan, Aliasghar Valipour, Zolfaghar Sabati, Fatemeh Hallajian

Student Research Committee, Abadan Faculty of Medical Sciences, Abadan, Iran

Iran is considered as one of the malaria-endemic countries in the globe. It is estimated that approximately 80% of malaria infections happen only in two provinces, Sistan-Baluchestan and Hormozgan provinces (in southeast and south of Iran, respectively) [1]. Based on formal reports, Iran is in the pre-elimination phase of the infection and elimination of malaria is the final goal, which is targeted by 2020[2]. The total positive clinical cases dropped from 15 378 to 960 between 2002 and 2017 in the country[1]. There are seven anopheline species as primary or secondary vectors of malaria in Iran including, Anophele (An.) culicifacies Giles (s.l.), An. dthali Patton, An. fluviatilis James (s.l.), An. maculipennis Meigen (s.l.), An.sacharovi Favre, An. stephensi Liston and An. superpictus Grassi (s.l.).These suitable vectors exist in several provinces[3].

In Iran, the first malaria-training course for antimalarial campaign was launched in 1945 and subsequently was continued between 1948-1956 with several control programs which resulted in significant reduction in malaria infection. In addition, the malaria eradication program was initiated from 1957 and continued till present[4]. It should be noted that a declining trend was observed in terms of malaria incidence in our country, Iran. However, despite continuous efforts and national investments in the past six decades,malaria may appear in some areas as a public health concern[1,4].However, to achieve malaria elimination, we need to monitor malaria infection among residents of endemic areas and also in immigrants/travelers of border cities. Hence, a descriptive crosssectional investigation was done in the border regions of Abadan and Khorramshahr counties in Khuzestan province (southwest of Iran) during 2013-2018. The current study aimed to describe the epidemiological aspects of malaria infections in malaria-elimination program regions of southwest Iran.

During the years, a total of 9 517 persons were included in the surveillance program. Brie fly, after physical examination by trained physicians, blood samples were taken. One drop of blood sample was placed on a microscopic slide and after Giemsa staining, was examined using light microscope to detect Plasmodium parasites. In addition, a structured questionnaire, including some demographic details, was filled out for each participant. All subjects voluntarily agreed to be tested. An informed consent was obtained from adult persons and parent or guardian of children less than 15 years old. This study received the approval from the Abadan Faculty of Medical Sciences Ethical Committee (IR.ABADANUMS.REC.1397.027).

Upon analysis, only two subjects were found positive (2/9 517;0.021%) for Plasmodium species as follows:

Case 1: Gender: Male; Age: 26 years old; Education level: diploma or lower; Nationality: Pakistani; Country of origin: Pakistan; Job:farmer; Causative agent: Plasmodium (P.) vivax; Clinical symptoms/signs: fever and chills; Rapid diagnostic test (RDT): positive.

Case 2: Gender: Male; Age: 35 years old; Education level: diploma or lower; Nationality: Pakistani; Country of origin: Pakistan; Job:laborer; Causative agent: P. falciparum; Clinical symptoms/signs:none; RDT: positive.

The infected persons were from Pakistan who have traveled to Iraq for visiting the holy shrines as pilgrims. Thus, both infections were categorized as imported malaria. Moreover, two positive cases were identified in a healthcare center located in the border region of Khorramshahr town (southwest of Iran) and Iraq during November 2017.

Although new positive malaria cases have been observed during past years throughout Iran, the current situation represents a satisfactory elimination in most provinces of the country. Malaria incidence decreased from 0.24/1 000 cases in 2002 to 0.01/1 000 in 2017. It is worth mentioning that autochthonous cases decreased from 45.70% in 2002 to 9.27% in 2017, while the imported cases have increased from 44.41% to 90.73% during these years[1].

In the current study, 9 288 Iranian and 229 non-Iranian subjects were screened. Among them, only two positive cases with Pakistani nationality were identified through microscopic method and then confirmed by RDT. In a recent retrospective study by Salmanzadeh et al.[5]in Khuzestan province (southwest of Iran), a total of 541 patients with Plasmodium infection were recorded between 2001-2014. Of these, 82 (15.16%) and 459 (84.84%) belonged to Iranian and foreign subjects, respectively. They concluded that "proximity to endemic countries has made the malaria campaign difficult; thus,regular monitoring of travelers and several rigorous control programs should be continued constantly until infection elimination in the province and, of course, in Iran". They also highlighted the key role of travelers which may contribute to the maintenance of malaria in malaria-elimination programmed areas of southwest of Iran[5]. The same findings were reported from other provinces[6,7]. In a recently published article in southeast of Iran (Saravan and Chabahar town in Sistan-Baluchistan province), among 765 immigrants, seven positive malaria cases (0.9%) were detected. Five and two subjects had P.vivax and P. falciparum, respectively[2].

The border counties of Khuzestan province (Abadan and Khorramshahr counties) are the main gateway for traffic of foreign nationals from Iraq, and thus, annually receives several millions of immigrants, pilgrims, and tourists. Accordingly, the risk of malaria incidence exists and needs more attention by policy makers.In the future years, more meticulous control programs should be implemented in the border towns of Khuzestan province.

Conflict of interest statement

The authors declare that there are no con flicts of interest.

Acknowledgments

We sincerely appreciate all staff at the healthcare centers in Abadan and Khorramshahr counties who assisted to collect the samples.