Epidemiological Characteristics and Temporal Trend of Human and Bovine Brucellosis Cases, Southern Iran,

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1 ENGIGRAR ANIGIRO Epidemiological Characteristics and Temporal Trend of Human and Bovine Brucellosis Cases, Southern Iran, VAHID RAHMANIAN 1, KARAMATOLLAH RAHMANIAN* 2, ELHAM MANSOORIAN 2, ABDOLREZA SOTOODEH JAHROMI 1, ABDOLHOSSEIN MADANI 3 ABSTRACT Aim: To determine temporal trend of human and bovine brucellosis cases in southern Iran, Methods: In this descriptive-analytical study, demographic and epidemiological data of all cases of human and bovine brucellosis reported and recorded by the relevant special care systems were enrolled, Data analysis was carried out using SPSS-18. Results: The average annual incidence of new cases of human brucellosis, during 2009 to 2016 was per populations and the incidence of bovine brucellosis was reduced from 17.6 per head of cattle in 2010 to 0 incidence rate in 2013 that showed a downward trend. Male patients accounted for 65.6% of 1140 patients with human brucellosis. A total of 79.7% of patients lived in rural areas and human brucellosis had the highest prevalence rate in (56 patients=18%) and then years' age groups (55 cases=17.7%). The highest prevalence rate was observed among livestock breeders (26%) and housewives (15.8%), respectively. Pearson correlation coefficient of (P=0.002, r=0.3), (P=0.006, r=-0.28) and (P=0.03, r=-0.79) was respectively obtained between number of cases of brucellosis and average monthly temperature, number of cases of brucellosis and the average relative humidity, the number of cases of bovine brucellosis and coverage percentage of bovine brucellosis vaccination. Conclusion: Malta fever is an occupational disease in Jahrom city, therefore, it is recommended to continue and strengthen dairy industry improvement and development program and livestock vaccination program, besides health education programs, as a strategy to prevent the disease in humans. Keywords: Malta fever, Bovine brucellosis, Epidemiology INTRODUCTION Brucellosis is a bacterial infectious disease between humans and animals. The disease is called Malta fever in humans and brucellosis in livestock 1,2.. A gram-negative bacterium called brucellosis is responsible for the disease that is eliminated by pasteurization and boiling 1,3. Type and complications of Malta fever differs depending on the bacterium transmitted from animals. This disease is usually caused by Brucella abortus and sometimes B. melitensis in cattle and is caused in sheep and goats by B. melitensis and sometimes B. ovis and B. abortus. B. melitensis causes the most severe state of the disease in humans. B. Abortus can cause subacute form of the disease and B. ovis is not pathogenic in humans Zoonoses Research center, Jahrom University of Medical Sciences, Jahrom, Iran 2 Research center for social Determinants of Health, Jahrom University of Medical Sciences, Jahrom, Iran 3 Research center for social Determinants on Health Promotion, Hormozgan University of Medical Sciences, Bandarabbas, Iran Correspondence to Dr. Karamatollah Rahmanian; Research center for social Determinants of Health, Jahrom University of Medical Sciences, Moahari St, Jahrom, Iran Tel: Fax: k.rahmanian@jums.ac.ir Malta fever is primarily transmitted to humans through consumption of contaminated dairy products or skin scratch and direct contact with meat or blood of the infected animal 1. Its symptoms manifest in the form of persistent or regular fever with alternating periods, abundant sweating, especially at night, fatigue, anorexia and weight loss, headache, muscle aches and general body pain 5,6. The disease has a broad global dispersion that is caused by the spread of infection in domestic and wild animals. It has been reported that approximately 500 thousand people are infected with brucellosis, and it has been estimated that only 4% to 10% of brucellosis cases are diagnosed even in developed countries 7. The disease is of utmost importance in most parts of the world, especially in developing countries in terms of its impact on public health and on socioeconomic status. Controlling the disease in animals led to a significant reduction in its incidence in humans in many developed countries; but the disease is relatively prevalent in developing countries, especially the Mediterranean region, West Asia and parts of Africa and America 1,3. Although human brucellosis in humans is rarely fatal, it can extremely cause disability. Disability 488

2 Vahid Rahmanian, Karamatollah Rahmanian, Elham Mansoorian et al weights resulting from this disease is considered 0.2 based on DALY calculation because of pain and decrease in productivity caused by the infection 6,8. Bovine brucellosis is eradicated or is in the process of eradication in many developed countries of the world, but is highly prevalent in other parts of the world. B. melitensis has also been eradicated in countries where careful planning and appropriate facilities are implemented in veterinary public health sector such as United State, Canada, northern European countries, Australia and New Zealand. The disease caused a miscarriage, reduced fertility as well as long-term permanent loss of milk production in infected animals 9. Although several strategies have been used for the control of human brucellosis in the world, nearly all of them are based on veterinary activities. The successful experiences of countries such as Portugal in the eradication of brucellosis suggest that the disease can be controlled and even be eradicated by adopting regular testing schedule, livestock slaughter and also their vaccination 2. Human brucellosis is traditionally endemic in the Eastern Mediterranean Region of World Health Organization, particularly Middle East countries and five of the ten countries with high incidence of human brucellosis include: Syria, Saudi Arabia, Iraq, Iran and Lebanon are located in this region 10. Many cases of the disease is reported in Iran due to its long borders and lack of supervision on imports of livestock, large number of tribal population, traditional husbandry methods, failure to supervise the production and distribution of dairy products and the lack of systematic implementation of vaccination, testing and slaughter of livestock 11,12. The average incidence of disease reported in Iran is 43.24/ and on average about 27,500 new cases have been reported annually that most of them are caused by B. melitensis species 7. Vaccines S19 (until 2004) and RB51 (since 2004) and ReV1 vaccines have been used in Iran respectively for calves &cattle and lambs, goats, sheep and yeanling. These pervasive and free vaccines are distributed and injected at the national level by the veterinary organization and the testing and slaughter program is implemented at the same time (This program has been suspended since 2004 for sheep and goats) 13. The prevalence rate is different depending on the culture and social fabric of communities in different areas; therefore, the present study aimed to investigate the epidemiological characteristics and temporal distribution of human and bovine brucellosis cases in Jahrom, Iran during the years MATERIALS AND METHODS In this descriptive-analytical study, demographic and epidemiological data of all cases of human and bovine brucellosis, which were reported and recorded by the responsible special care system, were enrolled in the study since the beginning of April 2009 till end of March After clinical suspicion and the test request by a physician, it is recommended to directly carry out Wright tubular test method on the serum samples (Wright-Test) in terms of definitive diagnosis criteria in order to homogenize the diagnosis procedure in health centers and public and private laboratories in Iran. Wright test equal to or greater than 1.80 indicates the acute disease, false-positive chronic disease caused by cross reactivity between Brucellas and other organisms. 2-ME test (2- Mercaptoethanol) was used in order to separate the three above modes. The titer equal to or more than 1.40 indicates the active disease and the need for drug treatment. 2ME with titer less than 1.40 doesn't usually indicate the active disease 1. Bovine brucellosis disease has been subject to livestock disease surveillance system and is recorded and reported in case of diagnosis and reporting of cases in the Islamic Republic of Iran. Therefore, data related to the livestock field, including animal population by the type of animal and year (goat, sheep, cow and calf), bovine vaccination coverage in years and bovine brucellosis cases based on the time of infection were extracted from Office for Combating Animal Diseases of Jahrom Veterinary Organization. Meteorological data (average monthly temperature in degrees Celsius, relative humidity in percent, and monthly rainfall in mm) were collected from the Meteorological Organization of the province. Data analysis was carried out using descriptive statistics and correlation analysis at the significant level of about The statistical analysis steps were performed using SPSS-18. Excel Software was used as the charting software. While carrying out this project, all ethical issues related to patients were observed. To do so, the name and last name of individuals were deleted and patient's information has been reported as a group. Also, this project is approved by the Ethics Committee of Jahrom Medical University with ID Number of IR.JUMS.REC RESULTS Overall, data of 311 patients with human brucellosis were studied. Male patients accounted for 65.6% of the participants. The mean age of patients was 489

3 Epidemiological Characteristics and Temporal Trend of Human and Bovine Brucellosis Cases 34.24±17.91 years and the highest frequency was reported in the age group years, with 56 patients (18%), followed by the age group of years with 55 cases (17.7%). The youngest and oldest patient was 2 and 85 years old, respectively. A total of 79.7% of total patients lived in rural areas and the rest were in urban areas. The highest prevalence rate was observed among livestock breeders (26%) and housewives (15.8%), respectively. Also, 98.4% of 1.6% of patients had Iranian and Afghan nationalities. With regard to demographic characteristics of patients with brucellosis, 286 (92%) and 273(87.7%) patients had a history of contact with animals in the past year and a history of consuming unpasteurized dairy products, respectively. Table 1: Demographic characteristics of patients with brucellosis, Classification Frequency% P value X 2 History of animal contact Yes 286(92%) <0.001 No 25(8%) Type of contact with animals Contact with living 171(55%) animals <0.001 Keep animals 18(56%) History of consuming unpasteurized dairy products Yes 38(12.3%) <0.001 No 161(51.8%) Type of dairy product Raw milk 161(51.8%) <0.001 Fresh cheese 30(9.6%) Cream 18(11.5%) Butter 24(7.75%) Colostrum 40(12.9%) Ice cream 1(0.3%) Herd and animal vaccination Yes 150(48.2%) <0.001 No 144(46.3%) Job Shepherd farmer 48(15.44%) Housewife Shepherd 25(8%) House wife 49(15.89%) Livestock breeders 81(26%) <0.001 Farmer 9(2.9%) Worker 17(5.5%) Student 38(12.2%) Others 25(8.03%) No children 19(6.1%) Age (year) 10 30(9.6%) (17.4%) (17.7%) (18%) < (17.4%) (13.8%) 60 19(6.1%) Among consumed dairy products, milk 161(51.8%) and colostrum 40(12.9%) patients) respectively had the highest consumption rate among patients. Also, a total of 74(23.8%) patients had a history of infecting other family members. Moreover, 150 individuals (48.2%) lived in areas where the vaccination had been practiced. Also, 47 patients (15.1%) were hospitalized due to their disease and 4 (1.3%) and 1(0.3%) patients were respectively diagnosed with orchitis and endocarditis, as complications of the disease (Table-1). Table 2: Laboratory and treatment characteristics of patients with brucellosis, Classification Frequency Wright test 1/40 1(0.3%) 1/80 44(14.1%) 1/60 106(34.1%) 1/320 73(23.5%) 1/640 44(14.1%) 1/ (10.9%) Undone 9(2.9%) 2ME test 1/20 9(2.9%) 1/40 69(22.2%) 1/80 79(25.4%) 1/160 47(15.1%) 1/320 29(9.3%) 1/640 11(3.5%) Undone 67(21.5%) Prescribed drugs Doxycycline+Rifampin 156(50.2%) Cotrimoxazole+Rifampin 42(13.5%) Doxycycline+Streptomycin 1(0.3%) Gentamicin+Cotrimoxazole 3(1.0%) Doxycycline+Rifampicin+Streptomycin 102(32.8%) Streptomycin+Cotrimoxazole+Rifampin 7(2.2%) Table 3: Frequency distribution of cases of human and bovine brucellosis, Inciden Incidence Year n% ce rate/ rate/100,000 n% 100,000 head of people cattle (15.1) (0) (12.5) (60.0) (10) (32.0) (14.1) (8.0) (15.1) (0) (18.6) (0) (7.7) (0) (6.8) Total 311(100) A total of 34.1% and 25.4% of patients had Wright test with titer of 1/160 and 2-ME test with titer of 1/80, respectively. The most prescribed drug 490

4 Vahid Rahmanian, Karamatollah Rahmanian, Elham Mansoorian et al regimen was rifampin and doxycycline (50.2%) (Table 2). The highest and the lowest incidence of brucellosis reported in the years , was observed in 2014(25.62%) and 2016(9.27%) per people. On the other hand, a total of 25 cases of bovine brucellosis have been recorded and reported during the present study. The highest reported incidence of bovine brucellosis was 17.6/100,000 head of cattle and no bovine brucellosis case has been reported since 2013 onwards (Table-3 and Diagram-1). Distribution of human and bovine brucellosis cases reflected the seasonal pattern as most cases of the disease have accumulated in late winter and early spring, which is called livestock calving season (Diagram-2). Pearson correlation analysis showed that there is a correlation between number of Malta fever cases in each month and the average monthly temperature (p=0.002, r=0.3), number of cases of Malta fever and the average relative humidity (p=0.006, r=-0.28); but there was no significant correlation between the number of cases of Malta fever and monthly precipitation (p=0.18, r=0.13) (Figure-1). On average, 3660 cows and calves and sheep and goats have been vaccinated in the City of Jahrom each year. There is a strong inverse correlation between the number of cases of bovine brucellosis and bovine brucellosis vaccination coverage rates (p= 0.03, r=-0.79); but there was no correlation between the number of human brucellosis cases and vaccination percentage of goats and sheep (p=0.85, r=-0.08). Diagram 1: Reported incidence of human brucellosis, bovine brucellosis and the number of animals vaccinated against brucellosis, (Blood drawing has been suspended in sheep and goats for serological testing in Iran since 2004). Number of cows and calves vaccinated per 10,000 head Number of goats and sheep vaccinated per 100,000 head Incidence rate of bovine brucellosis per cattle Incidence rate of human brucellosis in 1000 individuals

5 Epidemiological Characteristics and Temporal Trend of Human and Bovine Brucellosis Cases Diagram 2: Comparison of human and bovine brucellosis disease months, Fig. 1: Frequency distribution of cases of human brucellosis in terms of average monthly temperature (a), mean relative humidity (b) and monthly rainfall (c), A Temperature Human brucellosis B Humidity Human brucellosis

6 rainfall-cm Vahid Rahmanian, Karamatollah Rahmanian, Elham Mansoorian et al C Rainfall Human brucellosis DISCUSSION In the present research, the average annual incidence of new cases of the disease over the years of was equal to 17.12%/ individuals. However, the incidence of Malta fever in people has no equal and harmonious course in the past eight years so that the highest and lowest incidence rates of the disease related to the years 2014 (25.62) and the 2016 (9.27) per individuals, respectively. According to the report issued by Health Ministry's Communicable Disease Management of Iran the national incidence of human brucellosis was 21 cases per populations in 2012, which indicates a relatively favorable disease situation in Jahrom compared with the same situation at the national level. In a study, Dastjerdi et al. reported the average annual incidence rate of 12.1 cases per people 14. In a study, Etminani et al. reported the incidence of 26 cases per people in Khorasan Razavi Province 3. Also, Soofian et al. in Arak Province 15 reported the average incidence rate of 60 people per people. An incidence rate of 0.038% per people was also reported in a study conducted by Lee in China 16. The present study showed that the disease is more frequent in men (65.6%) than women (34.4%), which was consistent with results of other studies 3,14,17, which seems to be mainly due to men's occupational exposure and more contact with cattle. In this study, 79.7% of patients lived in rural areas and only 20.1% were in urban an area that is consistent with the results of other studies 12,14,18. This could be due to the fact the rural population are more in contact with cattle and consume higher amount of non-pasteurized dairy products compared with urban population. The highest prevalence rate was observed among livestock breeders (26%) and housewives (15.8%), respectively. Considering that 92% of patients mentioned a history of contact with animals and most of them were in contact with live animals and animals that being kept at home, it can be concluded that Malta fever is mainly an occupational disease in the city of Jahrom. Furthermore, the following factors have played a role in the incidence of the disease in Jahrom: large number of traditional animal husbandries, movement of infected animals, low level of knowledge, attitude and practice of struggling individuals about the ways of transmission and prevention of disease and lack of resources and facilities in the veterinary field for vaccination program and compensation for infected animals. In this research 23.8% of individuals with human brucellosis had history of infecting other family members with human brucellosis disease in the past 18 months 3,19. These results, in line with the results obtained in the present study, showed that lack of necessary training on the new cases of the disease as well as lack of diagnosis and proper control of infection reservoirs at the time of diagnosis and the common exposure of the members of a family to a source of infection (infected animals and unpasteurized dairy products) can be effective in infecting other family members of patients. In terms of criteria for diagnosis of human brucellosis, most patients had wright test with titer of (34.1%) and 2ME test with titer of 1.80 (25.4%). Also, only 1 individual had wright test with titer of less than 1.80 and 9 individuals had 2-ME titer less than 1.40 that was consistent with the results of other studies 3,20. Iran's National Technical Committee for brucellosis has recommended that the brucellosis treatment is necessarily of combined nature with more than one drug 1 and the most prescribed drug regimen was Rifampin+Doxycycline (50.2%) in the present study. However, the type of treatment regimens of choice depends on the availability of medicines, the patient's condition (such as pregnancy, children, etc.) as well as the patient's clinical status according to the physician view. The results of the current research showed that the 493

7 Epidemiological Characteristics and Temporal Trend of Human and Bovine Brucellosis Cases incidence rate of the bovine brucellosis was reduced from 17.6 per 100,000 head of cattle in 2010 to 0 in 2016 that shows a downward trend. This reduction can be attributed to the veterinary organization's prioritization regarding cattle vaccination in large units, less blood sampling and lack of diagnosis of cases in small domestic husbandry units. In a study on the prevalence of brucellosis in 2002 and 2006 in South Khorasan Province, Bokaei et al. showed that the incidence of the disease is 340 and 56 cases in 10,000 goats and sheep and heads of cattle, respectively 18. In a study, Esmaeili found that the number of infected animals was 0.08% of blood tested livestock in Iran in The above study showed that there is a positive correlation between the number of cases of Malta fever in each month and the average monthly temperature and there exists a significant negative correlation the number of cases of Malta fever in each month and the average relative humidity. It seems that the transition from winter to spring and summer and subsequently increase in the temperature and reduced moisture content leads to increased cases of human brucellosis by affecting pasture conditions in terms of animal husbandry, cattle breeding and increased contact between humans and animals. In their study in China, Lee et al. showed that there is a negative correlation between the average monthly relative humidity and human brucellosis 16. Various studies have shown that there is a correlation between cattle brucellosis infection and outbreaks of Malta fever in humans and as the contamination rate increases in animal populations, the incidence of brucellosis is increased in humans 22. Furthermore WHO considers livestock vaccination as the only suitable method to control the brucellosis infection that should be the first step towards eradication of the disease 23. The results of the present study revealed a strong inverse correlation between the number of cases of bovine brucellosis and bovine brucellosis vaccination coverage rates, which is consistent with the results of other studies 24,25. CONCLUSION According to the results obtained in this study, Malta fever is an occupational disease in the city of Jahrom where most patients people include men in the age group of adolescents and young adults who mainly have mentioned a history of contact with animals; therefore, raising awareness of groups at risk regarding ways of transmission, prevention, and complications of the disease requires more time and energy on the part of authorities of University of Medical Sciences and intersectoral collaboration between organizations and affiliates regarding disease control, especially the veterinary organization; therefore, it is recommended to continue and strengthen dairy industry improvement and development program and livestock vaccination program, besides health education programs, as a strategy to prevent the disease in humans. 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