Prospective case-control — Uses incident cases — Establish temporal sequence — Recall is not a serious problem — Records are easily obtainable tilahunigatu yahoo. Disease time series analysis. Vibrio cholerae are found in seas, rivers, and ponds of coastal areas of the tropical countries. You can login by using one of your existing accounts. In , 52 countries reported , cholera cases including deaths with a case fatality rate of 2. The authors would like to thank the authors that submitted their work for consideration to this Research Topic, the reviewers that critically evaluated these and the Frontiers Editorial Office for their help producing it. The secondary cases of cholera occur through fecal—oral transmission, and are related to poor hygiene, poor water, and sanitation environment [ 6 , 22 ].
In developing countries, every year 2. Zoonoses account for over half of all communicable diseases causing illness in humans [ 8 , 9 ]. These diseases are often endemic and include brucellosis, tuberculosis, salmonellosis, leptospirosis, rabies and others that are under diagnosed, underreported, and which disproportionately affect those who live nearest to animals especially in rural areas of Ethiopia. Even where zoonotic diseases do not cause death, they invariably deepen poverty and destroy livelihoods [ 10 , 11 ].
Many developing countries like Ethiopia face significant health issues especially zoonotic diseases whose control has been limited by a lack of integrated control measures [ 12 ]. In developing countries where resources are limited for the control and prevention of zoonotic diseases, selection and prioritization is important to use these resources efficiently [ 13 , 14 ]. In this context, use of Geographic Information System GIS is of paramount importance to map and study the epidemiological distribution of zoonotic diseases in space and time [ 15 — 18 ].
Even though the epidemiology of major zoonotic diseases in Ethiopia have long been established, to our knowledge there are no available maps of endemic zoonoses to show their spatial distribution and incidence proportion [ 8 , 19 ]. Mapping the epidemiological distribution and incidence of selected zoonotic diseases will help to identify vulnerable communities where zoonoses pose significant health threats and allocate the limited resources for their control and prevention [ 9 ].
Moreover, the inter-sectoral collaboration between different actors health professionals, veterinarians, environmentalists, and others is vital for the control and prevention of zoonotic diseases [ 20 ]. It is believed that there could be variation of diseases between sex, age, and geographical locations.
In the above context, the present study will contribute new data to provide an informed decision-making process leading to better control and prevention of zoonotic diseases in the study areas. The present study was conducted in three bordering regional states of Ethiopia namely Tigray, Afar and Amhara National Regional states from December to May Within these regional states Southern zone, zone two and North Wollo zone were selected purposively from Tigray, Afar and Amhara regions, respectively.
The seasonal classification in Ethiopia is mainly based of crop production and rainfall distribution. The human population of the study districts was also collected from the district planning and finance offices in based on the census conducted in Table 1 [ 22 ]. The human population data were collected to be used for mapping the epidemiological distribution and incidence proportion of major zoonotic diseases.
The study was a retrospective cross-sectional study using recorded patient medical data from health facilities. Recorded data on five zoonotic diseases such as rabies, tuberculosis, schistosomiasis, leishmaniasis and helminthiasis were collected based on the obtained case records patient medical data of Health Management Information System HMIS data from health centres and health offices, for the years to in selected districts.
All the health facilities available in each selected district were considered in the data collection. Moreover, data from the regional health bureaus were collected to triangulate the data from the health centres. To avoid potential sources of bias, expert views and literatures were consulted. There is an organized and standardized HMIS data recording system in human health facilities.
Clinical cases presented to the health facilities were diagnosed by physicians and health officers based on their clinical signs and symptoms. For TB and rabies, in addition to the clinical signs and symptoms, suspected specimens were confirmed by laboratory tests. The routine diagnostic approach used for TB at the health facilities was direct smear microscopy and rarely samples were confirmed by regional and national reference laboratories through culture and molecular approaches [ 23 ].
Rabid dog bite cases were considered as rabies positive and post-exposure prophylaxis was given to patients. Brain samples from rabid dogs were confirmed by histopathology and direct fluorescent antibody tests at the Ethiopian Public Health Research Institute [ 24 ]. Confirmation of schistosomiasis cases was performed by stool examination for the presence of schistosome eggs and in some health facilities, ultrasonography-based approaches were also used to detect for the development of fibrosis which is the typical indication for schistosomiasis cases.
Helminthiasis cases were diagnosed in health facilities based on clinical signs and symptoms. The disease surveillance and control teams in each of the health facilities were responsible for registering disease cases into the HMIS recording format and report them the district health officers. The district health officers also compile the data and report it to the zonal health officers. The zonal health officers report cases to regional health bureau and the regional health bureau report cases to the Federal Ministry of Health. All the disease cases registered are unique and there is no duplication of cases.
This is cross-checked by the disease surveillance and control exerts at various levels. In contrast to this, the data recording system at the veterinary clinics and health posts were found very poor. However, the registered data on the occurrence of animal diseases in the veterinary service centres were used in the present study. The research team visited each of the health facilities in the study districts and collected the recorded HMIS data after explaining the objectives of the study. The research team also submitted the ethical approval letters from the College of Veterinary Medicine and College of Health Sciences of Mekelle University for conducting the research.
The collected data on selected zoonotic diseases were fully anonymized and the researchers had no direct contact with the patients from whom data were collected. TB cases reported in this study were confirmed cases and the patients were under direct observation treatment DOT programs.
The collected data were entered into a Microsoft Excel sheet and summarized using frequency tables. All the collected patient medical data were analysed anonymously. Besides considering risk factors such as age, sex and seasonal variations, these data were used to map the epidemiological distribution and abundance of major zoonotic diseases in the study districts. The age classification used in the present study was based on the data recording in the health facilities. A correlation matrix was established using STATA version 15 software to see the association of disease cases in humans and animals.
GPS data altitude, latitude, and longitude of the study areas were collected from the villages where health centres health post and veterinary service centres found together or at least one was available S1 Table. The various functionalities of qGIS were used to map the distribution and incidence proportion of four major zoonotic diseases rabies, tuberculosis, schistosomiasis and helminthiasis in the study districts using the retrospective data results collected from health facilities Hospitals, Health centres and Health posts for the period — To compute a district level distribution of the zoonotic diseases, data-base at district level was created using data obtained from the health centres.
The GPS data collected in 1 km radius of the health facilities were used to indicate the location of the facilities in each of the study districts.
Then, disease distribution maps were generated S1 Protocol. Moreover, the research team had no any direct contact with the patients and used a fully anonymized data recorded by the diseases surveillance and control experts. In this study only five zoonotic diseases rabies, TB, schistosomiasis, helminthiasis, and visceral leishmaniasis VL were found recorded in the health facilities.
Of these major zoonotic diseases maps were developed for indicating the distribution and incidence proportion of four of the major zoonotic diseases rabies, TB, helminthiasis, and schistosomiasis. Since the number of VL cases recorded in the health facilities for the data collection periods was few, the result was summarized in tables. Though the data from Guba Lafto and Weldiya districts were collected independently, they were merged together for mapping purpose. Out of the total 1,, recorded disease cases at all health facilities hospitals, health centres and health posts in humans from to , 53, 4.
Out of the total zoonotic diseases, helminthiasis Both forms of leishmaniasis took the least share Table 2. The year wise distribution of the major zoonotic diseases is summarized in Table 3 , where the highest cases for TB and rabies 78 were reported in in the study areas. The highest cases for schistosomiasis were in and where 23 cases were reported in each year. According to the results of the present study, there was an annual decreasing trend of TB and rabies cases during the study period.
Regarding the incidence proportion of this disease per , population, 4. Rabies cases were higher during the autumn season whereas cases of helminthiasis, schistosomiasis and VL were higher during summer season Fig 2. The highest number of zoonotic cases, 5, Except VL, the other major zoonotic diseases reported in the present study showed a statistically significant difference among males and females. Higher incidence proportion of rabies was reported in females with respect to other diseases Table 4.
About the age group, the highest record of TB cases per , population , helminthiasis 17, However, the highest number of rabies cases were registered in individuals within the age group of 5 to 14 years Fig 3. The afore-mentioned retrospective data — on six major zoonotic diseases included in the present study were requested from the district agriculture and animal health offices. However, the data obtained were only for rabies and anthrax. Out of the 31 registered rabies cases in different animal species, 11 Additionally, 3 9. In each study district, there was considerable increase in rabies cases in humans as compared to rabies cases in animals Fig 4.
A total of 15 anthrax cases were reported in different animal species in the study areas from — Out of total recorded cases, 11 cases were observed in bovine and 2 cases each were reported in goats and camel. The highest number of anthrax cases 4 Rabies has the highest number of reported cases as compared to anthrax. Epidemiological distribution and incidence proportion for the four major zoonotic diseases were mapped using the functionalities of qGIS software and the results are presented in Figs 5 — 8.
The highest incidence of rabies The highest number of helminthiasis cases were registered in the health facilities of Guba Lafto andWeldiya, and Raya Alamata districts With regard to the incidence proportion of schistosomiasis, the highest cases were registered in Raya Alamata district health facilities 50 cases per , population followed by Guba Lafto and Weldiya 11 cases per , population. The other district health facilities reported less number of cases for the reporting period Fig 8. In this study, an attempt was made to map the epidemiological distribution and burden of the afore-mentioned major zoonotic diseases which have a public health importance using qGIS based on the data obtained from health facilities.
According to this study, out of the total human disease cases registered in the health facilities for the reporting period, 4. There was an annual decreasing trend in TB and rabies cases from to The decrease in the cases of TB and rabies through the years could be due to the continued health promotion services and measures undertaken by the government in controlling these diseases. The increase in the awareness of the community could also play a role for the decreasing trend in these diseases [ 26 — 29 ].
In the present study, the number of helminthiasis cases from the retrospective data were highest as compared to other diseases. The major helminthiasis cases that have public health significance could be taeniasis, ascariasis, trichuriasis and hydatidosis. These findings are also supported by previous prevalence estimates of different helminthiasis cases, which bears the highest burden among sub-Saharan African countries [ 30 , 31 ].
Sociodemographic data, clinical data, and evolution of the cases were analyzed across the two time periods and presented by number and percentage. This rate variation was compared to the average VL disease incidence rate variation in Brazil. The value was multiplied by and therefore represented the percentage variation of the rate. The decision to group and compare 6 and 8 years, to and to , respectively, does not affect the result interpretation, as a previous test found interpolation in the confidence interval of the mean incidence rates between the groups.
The spatial distribution of VL was evaluated by mapping incidence rates per municipality and comparing distributions between the periods and The categorization of rates by mapping, as shown in Table 1 , followed the cutoff suggested by the Pan American Health Organization Note: The crude rates, which are depicted in bold and italic, indicate high rates The difference between reports and the total number of cases 47 cases can be explained by missing data of the municipality. Data analysis was performed using Stata 9. The lowest rate was recorded in 1. There was an increase in the number of municipalities reporting VL cases Figure 1 , especially in the interior area of Brazil, which was previously an unregistered area.
The percentage of municipalities reporting VL cases ranged from Some states experienced a change in VL epidemiology and started to register vector or canine and human cases Figure 1. The number of VL cases in the Southern macroregion of Brazil increased; the region changed from a disease-free area in the first period to an area with autochthonous canine and human VL cases in the second period Only the Amazonas and Acre states did not have records of vector, canine, and human autochthonous cases.
Cases reported in Amazonas were considered not to be of autochthonous origin. These data were added in the manuscript to reinforce the need for VL surveillance, but were not the object of primary data collection.
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However, a literature review was used to gather this information and to make a relationship with the findings in this study. Aside from the Northeast region, all regions in Brazil showed an increase in the crude rate of VL in the second study period The Northern macroregion had the highest rate of VL, due to cases in the state of Tocantins, which had the highest number of new cases in the country Table 1. The mean percentage rate variation of VL in Brazil between the first and second period had increased by 1.
The profile of VL cases is outlined in Table 2. This data showed a predominance in males, the under 9 year age group, less educated members of the population or people who were not yet in school, and those living in urban areas. While the rate of patients treated for VL decreased in the second period, there was an increase in the number of deaths, especially in males.
A predominance of treatment abandonment was observed in males. VL: visceral leishmaniasis; HIV: human immunodeficiency virus; -: absence of the variable on the report form. Note: The percentages of the variables by sex were calculated per row and the total percentages were calculated per column. The percentages of the variable death by VL and death by other causes were calculated from the total number of deaths, which included death by all causes, because the databases were not the same in the two periods. The number of evolution cases did not reach the total number of cases in both periods due to missing data.
The incidence of visceral leishmaniasis coinfection with human immunodeficiency virus VL-HIV was highest in the second period , although there was missing data for this variable, as well as information on other clinical manifestations Table 2.
This study identified geographical changes in the incidence of VL cases, which was characterized by an expansion to previously disease-free areas; mainly to the interior of Brazil Figure 1 , but there is also a strong urbanization component Table 2. Despite the stability of the incidence rate in Brazil in general Figure 2 , the increase in the number of municipalities that commenced reporting cases of this important neglected disease deserves attention, as it confirms the territorial expansion.
The expansion over time Figure 1 , as shown by VL-free areas in the first period that reported vector, canine, or human cases in the second period , can be explained by simple adaptation of sandflies to varying temperatures and to the peridomiciles 21 , migratory movement of people with VL-contaminated dogs 22 , and to locals at the borders who have reported the disease These areas require active epidemiologic surveillance, because canine cases precede the human cases However, this state reported the presence of the sandfly Lutzomyia longipalpis in for the first time 31 , which increases the potential risk of the disease in humans at this site, as also pointed out in State of Rondonia The changes in VL epidemiology are also reflected in the extensive urbanization of cities, as the disease is predominantly associated with urban areas Table 2.
Previously, VL was considered a rural disease, however in the early s VL epidemics were recorded in an urban environment in Brazil 8.
Although it is not possible to state that urban transmission is different from that in rural areas, some factors that might be involved in the process of urbanization of VL in Brazil are the environmental modifications caused by anthropic action, caused by migratory movements and nonplanned urban occupation together with poor sanitation In addition, the main vector of VL, the sandfly Lutzomyia longipalpis , has adapted to the peridomicile, especially in the presence of domestic animals such as dogs The stability of the crude incidence rate in Brazil between the two time periods indicates that, even with an increase in the number of reported cases, there is no increase in the incidence rate, when population growth is considered.
Therefore, the incidence of VL had increased, especially when analyzed per macroregion and state separately. With the spread of the disease to other regions, this situation has changed and a decrease in the number of VL cases has been observed in the Northeast 21 , whereas the North reported an increase in cases Table 1. This expansion of the incidence rate is unrelated to the decision to subgroup the database into two time periods with an unequal number of years, considering that if an equal number of years were compared in the groups, a similar mean and interpolation in the confidence interval was found data not shown.
With respect to the spatial distribution, it is evident that municipalities that were previously free from the disease had changed their status. This may be due to the surveillance efforts in the Northeast, or to the emigration of the population This expansion of the incidence in VL cases to other regions has occurred without a sufficient amount of time to organize health services for diagnoses, perform appropriate follow-up of the cases, and to train health professionals, who without the correct knowledge might recommend an inappropriate treatment regimen for patients with VL 2 , The North of Tocantins State Figure 1 had a remarkably high VL incidence rate when the geographical distribution was analyzed.
This is mainly due to the extensive migratory flow of people from the Northeast, who live in poor housing conditions that lack urban infrastructure, sanitation and essential public services, such as garbage collection, health care and education These demographic and social problems are associated with the environmental impact caused by the deforestation in this state The most common degree is a Master of Public Health with a concentration or focus on epidemiology, however degree programs that focus solely on epidemiology are becoming more popular.
Some areas of specialization can include focus on cancer, cardiovascular disease, genetics, infectious disease, environmental causes and aging. Doctoral Degree — Some research epidemiologists may be required to hold a Ph. A doctoral degree provides graduates the skills and knowledge required to be at the top of their chosen field. The doctorate degree in epidemiology consists of one to three years of study and a doctoral dissertation. Those who earn a doctorate will find more opportunities available including more in-depth research studies or options for teaching. Students in a doctoral program can specialize in specific areas of epidemiology including cancer research or zoonotic infectious diseases.