Introduction
Ethiopia is believed to have the largest livestock population in Africa. This livestock sector has been contributing a considerable portion to the economy of the country. The livestock population of Ethiopia is estimated to be 70 million cattle, 42.9 million sheep, 52.5 million goats, 8.1 million camels, 13.33 million equines, and 57 million chickens. Of the total livestock population of the county, 34.4% are males and 65.5% are females [1]. The country’s economy mostly depends on livestock next to crop production. Moreover, the sector is irreplaceable in the livelihood of the population as a source of meat, milk, drought power, and income. However, despite having this massive amount of resources, the country is unable to exploit the sector entirely because of highly prevalent infectious diseases and a lack of appropriate disease control policy [2]. The predominant livestock production system in Ethiopia is extensive, where indigenous breeds are kept under low-input/low-output husbandry practices. The major biological constraints contributing to low productivity include the low genetic potential of the animals, poor nutrition, and the prevailing animal diseases [3]. The main effects of the diseases include mortality, low production, reduced quality of animal products such as milk and meat, decreased drought power, and risk of zoonotic diseases to man [4]. Ethiopia ranks highest in Africa in the health burden of zoonotic diseases [5].
In Ethiopia, there are several endemic and epidemic animal diseases caused by bacteria, viruses, protozoa, and parasites that compromise the productivity of the livestock sector. Among, the most important diseases are lumpy skin disease (LSD), contagious bovine pluropneumonia (CBPP), foot-and-mouth disease (FMD), blackleg, anthrax, hemorrhagic septicemia (HS), and so on [6]. The spatial distribution of major priority diseases among African countries in 2010 mirrors that of the previous years with a significant number of countries affected by LSD (63.26%), CBPP (48.97%), and FMD (48.97%) [7]. Risk factors for disease occurrences are host factors, environmental factors, pathogen factors, and climate conditions are the most important [8,9]. Most diseases are transmitted and gain entrance to the body by ingestion, inhalation, or through skin contact [10,11].
Priority diseases, caused by swiftly spreading pathogens that result in severe illness among numerous hosts, are a significant concern [12]. These diseases persist when both the pathogen and susceptible hosts are present, and transmission occurs effectively [13]. Managing such diseases involves treating cases, halting further spread, and monitoring control efforts [8,14,15]. In Ethiopia, efforts are focused on reducing the morbidity and mortality of production-related diseases, trade-limiting diseases such as FMD and CBPP, and economically impactful ailments such as blackleg and anthrax [16].
According to the district, estimated data recorded in woreda agricultural offices total livestock population of woreda is 205,214 cattle, 254,715 sheep, 239,541 goats, 7,238 camel, 57,188 equine, 215,522 poultry, and 14,580 dogs [17]. Even though there is an ample amount of livestock resources in the area, livestock disease and prevailing recurrent drought mostly remain the significant constraints limiting the sector’s productivity. The ongoing surveillance data analysis provided more information on the acquisition of data about the occurrence of reportable cattle outbreaks, the trend, and calculated proportion to indicate the distribution of reportable cattle disease outbreaks by animal, place, and time because there is no recorded surveillance data to quantifying the importance for detecting the trend and burden of major reportable cattle disease outbreaks in the districts as well as disease occurrence and evaluating the effectiveness of disease control program, identify problem with the quality of animal health surveillance data. Therefore, the present surveillance data analysis on major reportable cattle disease outbreaks will be initiated to conduct.
The objective of Frontline In-Service Applied Veterinary Epidemiology Training (ISAVET) is to develop transferable, critical thinking skills in the veterinary workforce to strengthen frontline preparedness, early detection, and rapid, effective, and efficient response to zoonotic diseases, interventions to transboundary animal diseases, emerging infectious diseases, and antimicrobial resistance within an integrative one health approach. The program is uniquely designed to deliver training through service to meet the critical need for veterinary field epidemiologists who can describe epidemiological events for animal-specific and zoonotic disease events. The program is launched in Africa under the Global Health Security Agenda project through the Human Resource action package/technical area with funding from United States Agency for International Development. The technical backstopping from Food and Agriculture Organization (FAO) Emergency Centre for Transboundary Animal Diseases teams, the Institute for Infectious Animal Diseases of Texas A&M University, the Ministry of Health, the Ministry of Agriculture (MoA), Animal Industry and Fisheries, and District local governments.
We are field-level veterinarians who have been certified to successfully complete the Frontline ISAVET program organized by the MoA in collaboration with the Food and Agriculture Organization of the United Nations. Our research study was part of the ISAVET curriculum compulsory required field activity products to graduate first conduct two data exercises, weekly surveillance reports, and systematic disease monitoring and data quality audits at the animal health office level. Second conduct one brief field study, field or outbreak investigation, survey or kap study, secondary data analysis, value chain mapping, and risk pathway analysis.
General objective: To identify significant reportable cattle disease outbreaks, and assess trends, distribution, vaccination coverage, and disease burden. A retrospective surveillance data analysis over seven years in Chinaksen Wereda, East Hararge zone, Oromia Regional State, Ethiopia.
Specific objectives: To evaluate the frequency of reportable cattle disease outbreaks, cases, and deaths, to analyze their spatial and temporal distribution, to determine disease trends and burden, and to assess vaccination coverage.
Materials and Methods
Operational definitions: Major priority reportable cattle outbreaks, 2017–2023. Based on the title of the project work the following are terms and their corresponding definitions.
Case Fatality Rate: Measures the severity of a particular disease by defining the total number of deaths as a proportion of reported cases of a specific disease at a specific time.
Analysis: This means an investigation of the component parts of a whole and their relations in making up the whole.
Data: This means a collection of facts from which conclusions may be drawn.
District: This means a region marked off for administrative purposes or for other purposes.
Morbidity: This means the relative incidence of a particular disease.
Mortality rate: This means the ratio of deaths in an area to the population of that area, expressed per 1,000 per year.
Outbreak: This means a sudden violent spontaneous occurrence of a disease.
Population at Risk: This means the population that is naturally susceptible to the disease.
Surveillance: This means the ongoing systematic collection and analysis of data about an infectious disease that can lead to action being taken to control or prevent the disease.
Suspected Case: This means an animal showing clinical signs overlapping the main characteristics of the disease.
TADs: This means transboundary animal diseases are those livestock diseases, which have high economic importance and have a nature of epidemic, pandemic, and sporadic.
Zone: This means a region marked off for administrative purposes or for other purposes but a little bit, it is wider than a district.
Kebele: This means the smallest administrative unit in Ethiopia, contained within a district.
Study Area
The study was conducted from May 2023 to August 2023 in Chinaksen woreda, East Hararge Zone, Oromia Regional State, Ethiopia. Chinaksen woreda is one of the 21 woreda of the East Hararge Zone, which was established in August 2005 G.C. (Gregorian calendar). It is situated about 643 km east of Addis Ababa, the capital city of Ethiopia. The total land area of Chinaksen district covers 661.721 km2, and it is bordered by Jarso District in the west, Tulu Guled District in the north, Jigjiga Somali Regional State to the east, and Gursum District in the south. Administratively, Chinaksen District is composed of 49 kebele and three small towns.
Geographically, the district is located between 9°30′ North latitude and 42°42′ East longitude, with an altitude of 1,550 to 1,816 m above sea level. Agro-ecologically, the woreda is divided into three main agro-ecological zones: Kolla (lowland) (56%), Woynadega (midland) (41%), and Dega (highland) (3%). The average temperature of the area is between 18°C and 26°C, respectively. The area receives a long rainy season from June to August and a short rainy season from March to May. The area is characterized by pastoral and agro-pastoral livestock productions, which are the most predominant. According to the estimated data recorded in the Woreda agricultural office, the total livestock population of Woreda includes 205,214 cattle, 254,715 sheep, 239,541 goats, 7,238 camels, 57,188 equine, 215,522 poultry, and 14,580 dogs, which are the main livestock species raised in the area. The district has a human population of 155,507 (male 75,719 and female 79,788) people Figure 1.
Study Population
All indigenous and crossbred cattle populations of all age groups and both sexes in the districts were included in the study.
Study Design and Study Period
A retrospective study design was carried out to conduct priority reportable cattle disease outbreaks of seven years data (2017–2023) which was extracted from the archives of the district office of Agriculture Animal Health Department outbreak report recorded databases as well as additional information was gathered from the Veterinary Epidemiology Department of East Hararge zone and Hirna Regional Veterinary Laboratory Center report. Disease outbreak reports were collected and recorded from outbreaks that occurred kebele of the districts. Diseases were prioritized based on their impacts on rural households, impacts on the market, value chains, morbidity, and the mortality of production-related diseases.
Figure 1.
Map of Chinaksen District where the studies were conducted.
Data Source and Collection
The occurrences of notifiable diseases in Ethiopia have to be reported monthly from the district level to the national epidemiology directorate within the Federal MoA. Data on the outbreaks of cattle in the Chinaksen district of the East Hararge Zone from January 2017 to August 2023 were obtained from the archived Monthly Disease Outbreak and Vaccination Activity Report (DOVAR)–retrieved data report filled for the last seven years in the district. When a suspected case of cattle outbreaks occurs in the village, Animal Health Technicians and Community Animal Health Workers (CAHWs) report to the district-level veterinarian or other animal health professional about the disease outbreaks; the district-level veterinarian pays a visit to the village where the outbreak occurred to make a tentative diagnosis based on the clinical symptoms observed. He/she then notify the Regional Veterinary Laboratory, which then conducts an epidemiological investigation to confirm the presence or absence of the disease. Diagnosis is usually done based on the clinical signs and other epidemiological features.
Sampling Procedure and Sample Size
The sample size was determined by the number of outbreaks found in the archives, i.e., the number of outbreaks reported in the district. For the line listing, the sample size of all outbreaks recorded per year was totally selected.
Data Management and Analysis
The data were obtained from the retrieved DOVAR report filled for the last seven years (2017–2023) from the archives of the Chinaksen District Office of Agriculture, Animal Health Coordination Department recorded outbreak report databases, from the East Hararge Zone Agricultural Office and HRVL Center. The data obtained were recorded in specially designed Excel line listing data collection template format. The records included information such as woredas, zone, species affected, index date, number of cases, number of outbreaks, number of deaths, number of animals vaccinated, and the population at risk. For this study, DOVAR reports of woredas were assessed, and reported outbreaks were extracted and recorded. After collection, the data were processed by editing, coding, and summarizing into tables/line listings in an Excel spreadsheet. Data were edited to check for completeness and accuracy in responses. Reports with missing responses and other inconsistencies were noted and corrected.
The data were analyzed using a descriptive Microsoft Excel data analysis package to summarize the number of reportable cattle outbreaks that occurred and calculate proportions to indicate the distribution of reportable cattle disease outbreaks (including cases and deaths) in time (distribution across different months, seasons, and years) and place (distribution in different kebele of the districts). The trend and distribution of reportable disease outbreaks by animal, place, and time were presented using pivot tables, graphs, and charts on the Excel sheet. The year was categorized into four seasons; long rainy (June to August), short rainy (March to May), early dry/cold (September to November), and dry/hot (December to February) season. The animal level morbidity, the mortality rate of the outbreak, and the case fatality rate were determined by dividing the number of deaths by the number of cases due to outbreaks.
Results
The result of these studies showed that a total of 31 cattle disease outbreaks were recorded at the wereda level from 2017 to 2023 with a total of 1,081 cases and 94 deaths reported. The largest number of cases was recorded in 2020 which was 268 (24.8%) and the least in 2023 which was 31 (2.9%). On the other hand, the highest number of deaths was recorded in 2021, which was 52 (55.3%) whereas the least in 2022, which was 1 (1.1%) death, was reported. Likewise, the greatest number of case fatality rate (CFR) was recorded in 2021 (19.7%), 2023 (16.1%), 2019 (10%), and 2017 (9.7%), while the least in 2020 (1.5%) and 2022 (1.7%). The morbidity rate was highest in 2022 (5.2%), 2018 (5.1%), and 2019 (2.9%), while the least in 2023 (0.6%). HS was responsible for the highest proportion of morbidity rate (2.40%), followed by LSD (2.18%), FMD (1.51%), blackleg (1.31%), anthrax (0.79%), and rabies (0.81%). LSD was responsible for the highest cases (36.1%) followed by FMD (29.8%), while blackleg and LSD were the leading causes of cattle deaths, which accounted for (55.3%) and (20.2%) of the deaths recorded, respectively. While, the lowest number of outbreaks, cases, and deaths of cattle occurred by rabies. However, the mortality rate was generally very low as summarized in (Table 1).
Table 1.
Number of outbreaks, morbidity, case fatality, and death reported by disease during the period 2017 to 2023 from Chinaksen districts.
| Disease | No of outbreaks | No of cases | No of deaths | PAR | Morbidity rate | Mortality rate | CFR |
| Anthrax | 1(3.2%) | 34 (3.1%) | 4 (4.3%) | 4,321 | 0.79 | 0.09 | 11.76 |
| Blackleg | 7 (22.6%) | 187 (17.3%) | 52 (55.3%) | 14,255 | 1.31 | 0.36 | 27.81 |
| FMD | 6 (19.4%) | 322 (29.8%) | 6 (6.4%) | 20,753 | 1.55 | 0.03 | 1.60 |
| HS | 5 (16.1%) | 147 (13.6%) | 12 (12.8%) | 6,134 | 2.40 | 0.20 | 8.16 |
| LSD | 11(35.5%) | 390 (36.1%) | 19 (20.2%) | 17,885 | 2.18 | 0.11 | 4.87 |
| CBPP | 0 | 0 | 0 | 0 | 0.00 | 0.00 | 0.00 |
| Rabies | 1 (3.2%) | 1 (0.09%) | 1 (1.06%) | 124 | 0.81 | 0.81 | 100 |
| Total | 31 | 1,081 | 94 | 63,472 | 1.69 | 0.15 | 8.68 |
Figure 2.
Number of outbreaks reported during 2017–2023 in Chinaksen districts, Oromia, Ethiopia.
Figure 3.
Trend of cattle disease outbreaks in Chinaksen districts from 2017–2023.
Based on the report of symptomatic diagnosis the outbreaks were caused by six diseases, namely anthrax, blackleg, HS, FMD, LSD, and rabies. The highest number of outbreaks reported were caused by LSD (35.5%), followed by blackleg (22.6%), FMD (19.4%), HS (16.1%), and anthrax and rabies 2 (3.2%) (Fig. 2).
The temporal distribution/pattern of cattle disease outbreaks was evaluated over the seven-year period and showed that the sporadic occurrence of disease was reported in the districts. The highest number of outbreaks from all causes was recorded in 2021, followed by 2018, 2020, and 2022, while the lowest in 2017, 2019, and 2023. CBPP outbreaks were not recorded during the period 2017–2023. Since the total number of outbreaks caused by anthrax and rabies were so small that it was not possible to clearly show the temporal pattern of the diseases Figures 3–5.
Sub locals have observed the spatial distribution of the seven diseases reported during the seven-year period. It was shown that more than 36.4% of LSD outbreaks were reported from two kebele (Tiro Sandare and Gella) and about 40% of HS reports were from Mulisa Igu. FMD outbreaks were reported from Ulanula, Gola waachu, Golmayo, Darbiga, Marar, and Qocar. Blacklegs were reported from Dagdher, Caacale, Kalaroga, Lugoo, Qobo-biqa, Orda 2ffa, and Migira, while rabies from Marar and anthrax from Amola kebele Figure 6.
Seasonal distribution of outbreaks from each disease is presented in Table 2 and Fig. 7. When overall data were grouped into seasons FMD outbreaks were reported in all seasons of the year. Higher numbers of outbreaks were recorded in the long rainy, early dry, dry, and short rainy season outbreaks in descending order. The highest frequency of occurrence especially due to blackleg and LSD was reported in the long rainy season (June–August, n=12, 38.7%) followed by the early dry/cold season (September–November, n=7, 22.6%) due to FMD and LSD, the lowest incidence was recorded in both the short rainy season and dry/hot season (n=6, 19%), respectively, were as HS, LSD, and blackleg were relatively high in these two seasons.
Figure 4.
Total number of cattle disease outbreaks, cases, and deaths in Chinaksen districts from 2017–2023.
Figure 5.
Temporal distribution of major cattle disease outbreak by disease type.
Figure 6.
Cattle disease outbreaks by Kebele of Chinaksen Districts (2017–2023).
Table 2.
Seasonal distribution of cattle disease outbreaks.
| Season | Total outbreaks | Disease | ||||||
|---|---|---|---|---|---|---|---|---|
| Anthrax | Blackleg | FMD | HS | LSD | CBPP | Rabies | ||
| Long rainy (June–August) | 12 (38.7) | 0 | 5 (71.43) | 1 (16.7) | 1 (20) | 5 (45.5) | 0 | 0 |
| Short rainy (March–May) | 6 (19.4) | 1 (100) | 2 (28.6) | 1 (16.7) | 1 (20) | 0 | 0 | 1 (100) |
| Early dry/cold (September–November) | 7 (22.6) | 0 | 0 | 3 (50) | 0 | 4 (36.4) | 0 | 0 |
| Dry/hot (December–February) | 6 (19.4) | 0 | 0 | 1 (16.7) | 3 (60) | 2 (18.2) | 0 | 0 |
| Total | 31 | 1 | 7 | 6 | 5 | 11 | 0 | 1 |
Figure 7.
Seasonal distribution of cattle disease outbreaks.
Outbreak burden by animal age animal was grouped into two categories: Young (1–3 years) and adult (>3 years). Most cattle outbreaks were reported from all age groups and the least were between twelve months and thirty six months of age. The highest cattle outbreak cases were reported from all age groups 600 (55.5%), whereas the lowest cases were between twelve months and thirty sixy months of age 237 (22%). The Highest cattle outbreak cases were reported from females 570 (53%), as indicated in Table 3.
The number of cattle vaccinated in the seven-year period against the seven diseases was presented in the following table and figures. It was noted that nearly 1 million cattle were vaccinated for all diseases during the period; however, the vaccination coverage varied from disease to disease. The highest proportion of vaccination was done for LSD (27.5%), followed by blackleg (24%), HS (22.4%), and CBPP (9.7%), and the lowest for FMD (1.2%) and rabies (0.41%) Table 4, Figures 8 and 9.
Discussion
In this study, the frequencies of major priority reportable cattle disease outbreaks, trends, distribution, vaccination coverage, and burden of disease conditions affecting cattle in Chinaksen districts of East Hararge Zone, Oromia, Ethiopia, during the 7-year surveillance data analyses period from 2017 to 2023 were determined. The current study revealed that a total of 31 priority cattle disease outbreaks with 1,081 cases and 94 deaths were reported in the study area. The study showed that consistently high numbers of outbreaks were reported from Mulisa Igu, Tiro sandare, Gella, and Marar sub-locals. The outbreak incidence indicated for the different sub-locals should be treated consciously because, in different parts of the area, there was a small number of outbreaks of cattle diseases which might be due to underreporting of outbreaks by the sub-locals might result in an underestimated incidence and there might be data quality problems at the wereda level during reporting a monthly disease surveillance report. A previous study [18,19] indicates that transport and communication were the two limiting factors in disease reporting in Ethiopia. These problems could result in irregular or absence of outbreak reports for some remote health posts.
Table 3.
Distribution of cattle outbreaks cases categorized according to age and sex.
| Disease outbreak | Total number of cases | Age grouping of animal in years | Sex | |||
|---|---|---|---|---|---|---|
| 1–3 year | >3 years | All age | M | F | ||
| LSD | 390 | 73 | 104 | 213 | 176 | 214 |
| FMD | 322 | 49 | 90 | 183 | 136 | 186 |
| HS | 147 | 30 | 18 | 99 | 77 | 70 |
| Blackleg | 187 | 85 | 31 | 71 | 98 | 89 |
| Anthrax | 34 | 0 | 0 | 34 | 24 | 10 |
| Rabies | 1 | 0 | 1 | 0 | 0 | 1 |
| Total | 1,081 | 237 | 244 | 600 | 511 | 570 |
Table 4.
Vaccine coverage of outbreak by disease in seven years (2017–2023).
| Year | Number of Cattle Vaccinated By Disease Types | |||||||
|---|---|---|---|---|---|---|---|---|
| Anthrax | Blackleg | CBPP | FMD | HS | LSD | Rabies | Total Sum | |
| 2017 | 15,678 | 51,711 | 0 | 0 | 21,865 | 61,721 | 0 | 150,975 (14.5%) |
| 2018 | 12,397 | 32,157 | 0 | 0 | 26,259 | 29,461 | 0 | 100,274 (9.6%) |
| 2019 | 43,160 | 20,000 | 0 | 8,000 | 27,460 | 42,000 | 0 | 140,620 (13.5%) |
| 2020 | 14,498 | 28,962 | 4,000 | 400 | 32,133 | 6,000 | 543 | 86,536 (8%) |
| 2021 | 19,670 | 41,822 | 32,340 | 2,000 | 46,401 | 50,567 | 0 | 192,800 (18.5%) |
| 2022 | 18,707 | 43,343 | 14,796 | 549 | 48,877 | 39,774 | 1,265 | 167,311 (16.1%) |
| 2023 | 30,820 | 31,793 | 49,468 | 1,053 | 30,308 | 56,400 | 2,456 | 202,298 (19.4%) |
| Total | 154,930 (14.9%) | 249,788 (24%) | 100,604 (9.7%) | 12,002 (1.2%) | 233,303 (22%) | 285,923 (27%) | 4,264 (0.41%) | 1,040,814 |
Figure 8.
The trend of vaccinated cattle in Chinaksen districts from 2017–2023.
The present study revealed that a total number of cattle disease outbreaks were caused by LSD (35.5%), blackleg (22.6%), FMD (19.4%), HS (16.1%), anthrax (3.2%), and rabies (3.2%) in decreasing order of their proportion which is similar to the finding of [20,21]. Although HS (2.4%) was the leading cause of morbidity according to the proportion of cases observed followed by LSD (2.18%), FMD (1.51%), blackleg (1.31%), rabies (0.81%), and anthrax (0.79%) in descending order there was strong agreement with [18], the highest case fatality rate was estimated for rabies, followed by blackleg.
Figure 9.
The number of cattle vaccinated by disease types from 2017–2023.
Analysis of the temporal pattern of disease occurrence over the seven-year period showed a significant fluctuation in the number of outbreaks. This change is associated with the application of effective prevention and control measures such as prophylactic vaccination because the annual vaccination coverage shows a considerable increase over the reporting period there was strong agreement with [18] were as contradicts with the result of other studies [22].
Regarding the seasonality of the diseases, cattle outbreaks were recorded in all the seasons of a year, and more outbreaks of disease were reported during the long/heavy rain season (June–August), which is in agreement with other studies [23,24], which comes after the short rainy season and outbreaks were relatively lower in the short rainy season (March–May) and dry/hot season (December–February) which is in agreement with other studies [20,21].
Blackleg was also responsible for the highest proportion of deaths (55.3%) over the seven-year period and its outbreak was reported in the long rainy (71.43%) season. This is nearly similar to the study conducted in India by [25] (33.03%) from season March to May. The seasonal occurrence of the disease is mainly observed in long rainy (June–August) followed by early dry (September–November) seasons which indicates that the occurrence of the disease depends on seasons. Outbreaks are often associated with alternating heavy rainfall, drought, climatic change, and environmental changes like high temperatures [26].
For this retrospective data, the highest number of outbreaks was held by LSD (35.5%), followed by blackleg (22.6%) and FMD (19.4%). This indicates that the parts of the area that receive relatively high rainfall for a reasonable period are conducive for the replication and survival of blood-feeding arthropod vectors and then for the spread of the disease in the geographical area. This is an agreement with [27,28]. Blackleg is associated with areas of high humidity and occurs during rainy seasons. There is an agreement with [29].
FMD was the third major cause of disease outbreak that occurred in the study area during the nine-year period next to blackleg. The number of outbreaks increased during early dry and rainy seasons, probably due to the favorable environmental conditions of dry weather, dry winds, and moderately high relative humidity. This is also the time of the year when migration and movement of livestock are common, especially in rural livestock farmers [30]. The district is characterized by a pastoral production system where animals travel long distances and can cross national boundaries. This can facilitate contact between different herds from different localities including neighboring countries and wild ruminants, which are continuous sources of infections. Seasonally, the highest number of FMD cases reported was found to be registered in the early dry season (50%), followed by rainy seasons (19.4%) [21,22]. The reason for the highest occurrence may be due to the massive movement of the cattle population to seek pasture and water points. Therefore, many herds of cattle meet at such places, thereby hastening the spread of infection from one herd to another [31].
HS was ranked fourth in its contribution for the major cause of disease outbreaks recorded (16.1%) during the seven-year period next to FMD. It is a fatal septicemia, which is influenced by the season of the year. Its incidence was highest during the dry season. This finding was in strong agreement with [22,18]. The occurrence is mostly in the transition period from wet season to dry or cold weather. This is consistent with [25] the seasonal variations and mortality pattern of HS was found that the mean HS mortalities increased with an increase in rainfall. Moist conditions also prolong the survival of the HS organism (P. multocida), and thus, the disease tends to spread more rapidly during the rainy season when land cultivation also brings about the movements of animals [22].
Although anthrax ranked least in its contribution to the outbreaks recorded, it was responsible for the third highest case fatality rate (11.7%) which agrees with [21]. It is true that anthrax is a per-acute disease that causes sudden death in livestock and very important cattle disease among others. Anthrax has a great impact on human social life in that it causes wealth loss (per-acute death of cattle), zoonotic importance to humans, and sometimes, ignorance of areas where carcasses were dropped. Anthrax outbreaks were recorded in the short rainy season (100%), which strongly agrees with the study conducted in Bangladesh [22]; higher in the short rainy (25.3%) and long rainy seasons (18.2%). Contradict with [32] early dry (27.1%) and dry (29.4%) seasons than in the short rainy season. The cases of anthrax were seen to occur more commonly in the short rainy (spring season) (100%) than in the other seasons. This report relatively agrees with [33]. Because this season is often hot and the condition is favorable for spore formation, hence, it is likely true that anthrax can relatively occur at a higher rate in the short rainy (spring) seasons [8] stated that animals become readily infected with anthrax when the minimum daily temperature is above 15°C. Furthermore, the animals crowd together at drinking points as water sources become scarce. The outbreak occurred during the hot and humid transition period between the dry season and the wet season. The soil was also significantly disturbed during this time (cultivation season), which possibly disturbed old anthrax gravesites. This agrees with the concept of [34].
This study shows the total suspected cases of cattle outbreaks were recorded in more age categories of >3 years. This may be indicative of prevailing passive maternal immunity and low frequency of exposure. This report consistent with [35] reported that suckling calves showed the lowest attack rate, though the dynamic model did not show higher susceptibility to infection. The study revealed high outbreaks (55.5%) in adults, in which the maternal immunity level drops and exposure to diseases, as age increases.
Generally, outbreaks develop when a large population of susceptible animals is present. If immunized animals are present in the herd, then outbreaks cannot occur until a sufficient number of young, non-resistant animals have been bred or non-immune animals from outside are introduced in the herd [36]. Vaccination programs are effective when a large proportion of the population is protected usually at least 72% of the susceptible cattle need to be vaccinated [37]. The result of the high proportion rate shows that due to a lack of attention to the Prophylaxis Vaccination of animals in the area [20], the vaccination programs have, however, not been carried out regularly according to manufacturer’s recommendations which leads to inefficient vaccinations. Regular prophylactic vaccination can successfully eradicate the disease but areas are still reacting to outbreaks; this happens possibly due to security problems in the area, lack of funds to follow prescribed vaccination schedules, lack of good veterinary infrastructure, unable to control animal movements, and poorly understood the epidemiology of the disease. This constrains the ability to implement control strategies suitable for the districts.
Retrospective studies, based on data collected through passive surveillance, have contributed greatly to understanding animal disease epidemiology [38]. For a resource-limited country, passive surveillance can also play an important role in the overall surveillance system. However, the findings in this study need to be interpreted with caution because of the likely biases in the reporting system; there has been no organized regular flow of reporting the surveillance for the diseases from sub local to wereda, some underreporting outbreaks (e.g., anthrax) may have occurred due to a lack of awareness of farmers, limited manpower restricts the ability of the veterinary to respond to all reported cases.
Limitation
All a notifiable disease outbreak, all cases and deaths associated with reportable outbreaks are mandatory to report to the Zonal and Regional Veterinary Laboratory. For this retrospective study, the secondary data were obtained from the archives of the Chinaksen Wereda Office of Agriculture, Animal Health Department recorded outbreak report databases and additional information was gathered from the zonal and hirna regional veterinary laboratory center annual report. The record has faced the problem of having limited access to data reports from some kebele/village of Wereda. Due to this limited access, redesign or restructure my study. The reasons for limited access to data are that no animal health activities have been carried out in this kebele due to ethnic-based conflicts arising in the area that significantly cause underreporting of outbreaks associated with the regular passive surveillance system. Some reporting biases have occurred from some kebele that is unexpected in a disease-endemic area. Because of no organized regular flow of reporting the surveillance diseases data or limited attention for disease reporting from kebele to wereda level.
Disease outbreaks were reported based on tentative diagnoses made by district offices. However, this has no more influence on my research finding it may not be critical since anthrax, LSD, FMD, HS, and rabies cases are not difficult to diagnose in endemic areas based on clinical signs, absence of regulation forcing professionals on compulsory reporting of disease outbreaks. Finally, my research findings are still reliable and valid despite these limitations.
Conclusion and Recommendations
This is the first retrospective study to provide a comprehensive analysis of the most reportable outbreak of disease affecting cattle in their localities based on the impact of the disease on the morbidity and mortality of cattle outbreaks, frequency of occurrence, and their distributions. The present retrospective study of disease outbreak data revealed that LSD, blackleg, FMD, HS, anthrax, and rabies were the major causes of reportable disease outbreaks in cattle in the district. Based on the retrieved data, LSD was noted to be the leading cause of disease outbreaks in cattle followed by blackleg while anthrax and rabies accounted for the least proportion of outbreaks. The occurrence of outbreaks was mainly season dependent. Seasonally, the dominant disease outbreak occurred in the long rainy season. The vaccination coverage of the study area was found to be smaller than the recommended level that is about 1 million cattle were vaccinated in a seven-year period. The findings from this study can be used as baseline epidemiological data for further study to understand the impact and epidemiology of cattle disease outbreaks and the basis for broader planning of prevention and control strategies for these diseases.
Based on the above conclusion, the following recommendations are forwarded:
- Outbreak investigation in the area was based mainly on symptomatic diagnosis and history from farmers. Thus, veterinarians working at the district level need to be supported by confirmatory diagnostic techniques specific to each disease.
- The district should provide regular training and supervision for animal health professionals and paraprofessionals on data collection, reporting, and analysis.
- Continuous data analysis and feedback to all stakeholders should be conducted on a regular basis to improve the quality of animal surveillance data.
- A retrospective study has shown that cattle disease outbreaks occur in seasonal dependents. This initiates the need for the implementation of awareness creation among veterinarians and strategic disease prevention programs through vaccination, which should be considered before the anticipated season of outbreak for each disease.
- Enhancing the awareness of livestock keepers about the impact of transboundary animal diseases and some cattle zoonotic importance.
- The district should allocate sufficient resources and coordinate with other stakeholders to conduct a timely and comprehensive vaccination campaign for the most prevalent and impactful diseases.
- Conduct Intensive follow-up studies to further identify the cause of outbreak occurrence and its related risk factors in the area.
- To change the approach and attitudes of livestock policymakers to more client-oriented the chances of fostering effective national animal health services that are inclusive of all livestock producers and farming systems through coordination, planning, and implementation of national control programs; disease surveillance, early warning measures, epidemiological analysis, risk analysis as an input to quarantine, and animal movement controls by providing an enabling legislative framework.
List of Abbreviations
CAHWs: Community animal health workers; CBPP: Contagious bovine pluropneumonia; CDC: Center for disease control and prevention; CFR: Case fatality rate; CHWAO: Chinaksen wereda agricultural offices; CSA: Central Statistics Agency; DOVAR: Disease outbreak and vaccination activity report; ELMP: Ethiopia livestock master plan; ETWW: Eco travel world wide; FAO: Food and agriculture organization; FMD: Foot-and-mouth disease; HRVL: Hirna regional veterinary laboratory; HS: Hemorrhagic septicemia; LSD: Lumpy skin disease; LDMFSB: Livestock disease management and food safety brief; PAR: Population at risk.
Acknowledgment
The authors praise Almighty God, who helps and enables them to finish their duties. The authors would like to extend many thanks and appreciation to their beloved mentor, Dr. Chernet Balcha, for his invaluable, persistent, and unlimited encouragement and support given until the commencement of the study that would not have been possible without their patience, advice, and assistance. The authors would like to acknowledge the Food and Agriculture Organization of the United Nations (FAO), the MoA, and the College of Veterinary Medicine and Agriculture of Addis Ababa University, Ethiopia, for the provided financial support for this study as well as ISAVET training. They also acknowledge the Oromia National Regional State Livestock Development Promotion Agency, Hirna Regional Animal Health Diagnostics and Investigation Laboratory, Veterinary offices in the East Hararge zone, and Chinaksen Agricultural offices for providing surveillance data and willingness and commitment to support the success of this work.
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