An epidemiologic survey of animal bites in Shemiranat, Tehran, 2009-2012

Discussion

This study is the first assessment on collected surveillance data in Shemiranat Health Center. The mean age of registered patients in this study was higher than similar studies in national and international scale (Dadipour et al., 2009; Amiri et al., 2009; Charkazi et al., 2013). Based on data from general census of population and housing in 2006, number of aging people in north and northeast was high (National Population and Housing Census, 2011) and this finding is justifiable by considering that high range of registered cases in Shemiranat Health Center were from this region. In this study, 65% of the registered cases were men which was in accordance with some studies (Dadipour et al., 2009; Aldavood et al., 2011; Riahi et al., 2012; Dehghani et al., 2013; Simani et al., 2002; Majidpour et al., 2003) and differed with some other studies (Freeman et al., 2005; Pandey et al., 2002; Quiles-cosme et al.,  2000). This gender difference is due to more contact with animals, more conscious risk taking, spending more time outdoors (Riahi et al., 2012) and more assertive in getting involved by animals (Rezaeinasab et al., 2007) in men compared to women. Furthermore, large number of employed men rather than women and more cautiousness of women at work or outdoors could be some other reasons (Riahi et al., 2012). There was no gender difference in regard to the age of patients in this study. In a study in USA, the bitten men have lower mean age than women (Freeman et al., 2005) contrarily, in a study in Turkey, mean age of patients in men was higher than women (Kilic et al., 2006).

The frequency of registered cases was high in age group 20-29 years which were similar to other three reported studies in Tehran and Tabas (Aldavood et al., 2011; Eslamifar et al., 2008; Riahi et al., 2012). Some other studies also showed different frequency in various age groups (Dadipour et al., 2009; Aldavood et al., 2011; Fayaz et al., 2011, Bahonar et al., 2008; Dehghani et al., 2013;  Razaeinasab et al., 2007). It is notable that, none of these results were based on the incidence rate. In past two decades, the structure of age has significant effect on Iranian and the population growth was declined (decrease in young and increase of aging population). Based on the census in 1996 and 2006, Iranian population has been in transition (National Population and Housing Census, 2011). Therefore, this population transition must be considered interpreting age differences. The incidence rate of animal bite was not calculated in this study. The incidence rate was taken into the account in limited studies (Sabouri et al., 2012; Majidpour et al., 2012). At the present study, 97% of registered cases were lived in urban area. This finding was in conflict with other studies (Dadipour et al., 2009; Sabouri et al., 2012; Fayaz et al., 2011; Eslamifar et al., 2008; Riahi et al., 2012; Bahonar et al., 2008; Amiri et al., 2009; Charkazi et al., 2013; Dehghani et al., 2013; Razaeinasab et al., 2007; Majidpour et al., 2012). Since, neither in the present study nor in other reports the incidence rate in urban and rural area was not determined, this conflict is not interpretable. Based on 2011 census, as more than 90% of people lived in urban area of Tehran and Shemiranat area, the finding of this study is justifiable.

The most frequent animal bites were occurred in spring in the present study as reported by some similar studies in Iran (Dadipour et al., 2009; Eslamifar et al., 2008). Season difference was not evident in some other studies (Riahi et al., 2012; Amiri et al., 2009). Animal bite was reported in spring and winter in a study (Bahonar et al., 2008) in which the more effort of animal to find food was proposed as the reason of its increase in winter. The correlation between season and the number of ulcers was not evident in this study as was found in AghGhala (Charkazi et al., 2013). In this study, the most animal bites occurred by dog which immediately followed by cats. This finding was similar to some previous studies (Riahi et al., 2012; Amiri et al., 2009; Dehghani et al., 2013; Quiles-cosme et al., 2000). Men are bitten by dogs more often than women (3 versus 1), whereas women are more often bitten by cats (3 versus 1) (Eslamifar et al., 2008). Similar to other previous studies, frequency of animal bite by domestic dogs was higher than stray dogs in this study (Eslamifar et al., 2008; Fayaz et al., 2011; Riahi et al., 2012; Dehghani et al., 2013). Lack of controlling and removing of stray dogs and poor management of domestic dogs could be the reasons of this result. In this study, 65% and 27% of registered cases had ulcers in upper and lower limb, respectively that was in agreement with studies in Iran and overseas (Eslamifar et al., 2008; Riahi et al., 2012; Quiles-cosme et al., 2000). However, legs and hands were reported to be the more frequent bitten organ by  numerous Iranian studies (Dadipour et al., 2009; Sabouri et al., 2012; Fayaz et al., 2011; Bahonar et al., 2008; Amiri et al., 2009; Dehghani et al., 2013; Majidpour et al., 2012; Razaeinasab et al., 2007). Availability of the legs to be bitten by animal, using legs as the first physical defense part of body and differences in anatomical classification of bitten organ are some attributed reasons for the observed variations in various findings (Charkazi et al., 2013; Sabouri et al., 2012; Dehghani et al., 2013). However the most frequent attacked areas were legs and hands together indicating that these organs have high risk of being targeted by animals. In children result is different, as shown in this study, the percent of injury in areas of head, face and neck were in higher in children than adults. In this regard, Pandey and et al (2002) found similar results of this study.

There was no correlation between residential status and attacked organs in the present study. While Amiri and Khosravi (2009) showed more injuries in legs and hands in rural and urban areas, respectively in Shahrood.

In this study, 76% of ulcers were superficial and only 18% of them were deep wounds. This finding was in coordination with other studies (Dadipour et al., 2009; Fayaz et al., 2011; Eslamifar et al., 2008; Riahi et al., 2012; Amiri et al., 2009). This finding shows that proper notification about rabies has resulted in rabies risk to be taken seriously by patients despite suffering from superficial wounds. In the present study, no gender differences were found in the method of washing the ulcers, type of disinfectants and completion of the treatment. This finding shows that washing and disinfecting the wounds are as important practice for men as for women. A total of 50% of registered cases received rabies preventive treatment till 5 hours after attack. Fayaz and et al (2011) revealed that 60% of patients received rabies preventive treatment till 6 hours after bite. There was no correlation between delay in receiving treatment and residential area. This correlation was shown in Shahrood (Amiri and Khosravi, 2009). This conflict could be due to higher developmental parameter such as education, access to information, health and treatment, economic, infrastructural and etc. in Tehran province compared to other provinces.

Based on the accessed data, fate of 77% of attacked animals was unknown and 22% were reported to be alive after 10 days. These proportions in Shahrood city were 15.6 and 82.3 percent respectively (Amiri and Khosravi, 2009). The higher percent of live animals after attack was due to the involvement of some other animals such as donkey, sheep and etc. as attacking animals in the calculations. The chasing animal fate till 10 days was specially done for wild and domestic carnivores.

One of the main problems in relation to the prevention and control of rabies is the lack of consistent care and regular reporting. This problem has led to lacking accurate and update information on this field (Bahonar et al., 2008). Collection, analysis and evaluation of epidemiological data are more important in planning, organizing and controlling rabies (Sabouri et al., 2012). Rabies is a serious outcome in animal bite patients. Eight countries in Asia (Japan, Malaysia, Hong Kong, Singapore, Taiwan, Qatar, Bahrain and the United Arab Emirates) have eradicated the rabies (Sabouri et al., 2012). Rabies with an incidence rate of 0.05 per million in humans is endemic in Iran and it is relatively controlled by efficient PEP treatments. However, it is endemic in dogs as well as wild animals (http://www.meereb.info). Due to imposed cost of each animal bite to health care system, preventative measures to avoid animal bites should be a priority practice (Riahi et al., 2012). Management of rabies because of economic and social outcomes is a major priority for Ministry of Health and Medical Education (Eslamifar et al., 2008). Based on socio-economic and residential area differences the epidemiology of animal bite is varying, and some confounders such as age and occupation may also be effective in causing these differences (Eslamifar et al., 2008). Most recent studies showed increasing number of animal bite (Sabouri et al., 2012, Zeynali et al., 1999; Charkazi et al., 2013; Dehghani et al., 2013; Razaeinasab et al., 2007). This increase is attributed to following reasons:

-                      Increase of public awareness about dangers of animal bite by implementing educational programs.

-                      Improvements in the health care and in monitoring and reporting system, and increasing number of health centers that has facilitated access of bitten patients to this centers.

-                      Reduction in the activity of stray dogs euthanized committee (Charkazi et al., 2013) and consequently increase in stray dog number.

-                      Moving the neighboring wild animals into residential areas due to ecological changes (Razaeinasab et al., 2007).

The successful methods for controlling rabies in wild animals are used in various countries which can be useful in Iran too (Fayaz et al., 2011). Expansion of veterinary clinics for vaccination of pet dogs, observation of the suspected biting animal, and public education campaigns (together with the application of post exposure prophylaxis [PEP] following a dog bite) during the 1950s and 1960s were simple and effective strategies for the management of rabies in dogs in United States. However, these strategies were not directly applicable to the management of rabies in wildlife (Hanlon et al., 1999). The control program of rabies in wildlife includes: removing the reservoir species, eradication of rabies in reservoir species; protecting sensitive species against rabies infection from reservoirs. In addition, activities that can be reduce opportunity and possibility of confronting wild animals with humans must be implemented. For example, proper management of waste disposal, removal and destruction of nests of these animals from nearby residential areas and proper food storage are some successful strategies (Rupprecht et al., 2001).

In order to prevent animal bites and to perform early preventive treatment, more educational activities in health sector should be performed. All responsible institutions and organizations, especially the media, including radio, television and newspapers, national and local education, municipalities, veterinary organization, universities and health and medical centers, can play a major role in this mobilization. The Ministry of Health and Medical education as a custodian of this program, should take over the task of planning and creating a harmony between all responsible units. This education must include below centerpieces.

•Educating the public, especially children, adolescents and youth about how to deal with domestic, stray and wild animals.

•Specific training of pet owners about vaccinations, collar placement and how to deal with these animals inside and outside the home.

•Training of administrators and municipal officials about how to reduce the number of stray dogs and vaccination of dogs without killing them.

•Cooperation and public participation in environmental sanitation and waste collection and landfill.