Retrospective analysis (2018-2021) of respiratory diseases in poultry, diagnosed at The Veterinary Services Laboratory, Kumasi, Ghana

¹School of Veterinary Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, ²Kumasi Veterinary Laboratory, Amakom, Kumasi, Ghana

^&Corresponding author
Benjamin Obukowho Emikpe, School of Veterinary Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana

Introduction    

Poultry farming is an essential component of the agricultural sector in many countries. It provides direct and indirect job opportunities, hence an important source of income for many [1,2]; it is a source of animal protein and provides organic manure to crop farmers. The poultry industry is an important component of Ghana´s economic growth and contributes to a reduction in poverty in both urban and rural areas [3,4]. In Ghana for some years now, the growth of the poultry industry has been limited, due mainly to the high cost of inputs, particularly poultry feed [5], and frequent disease outbreaks [1,2]. Other researchers also reported that poultry farming is combated with several diseases, including respiratory infectious diseases, which slow down production [6,7]. Although respiratory infections impact negatively poultry welfare and productivity, they are largely not very much studied in most African countries [8].

Common respiratory infections in poultry worldwide include Infectious Coryza (IC), Mycoplasmosis, Aspergillosis, Newcastle Disease (ND), Infectious Bronchitis (IB), Avian Influenza (AI), and Infectious Laryngotracheitis (ILT). Clinical indicators including gaping, sneezing, coughing, nasal discharge, and respiratory distress result from significant damage to various respiratory tract tissues [9]. In Ghana, the frequently diagnosed respiratory infectious diseases in poultry are Newcastle disease, Avian Influenza, Mycoplasmosis, Infectious Coryza and Aspergillosis. Ashanti region is the second largest poultry-producing region in Ghana, however, information on the prevalence of respiratory diseases in poultry in the region is limited. This study, therefore, determined the prevalence of common respiratory diseases in poultry, and their annual, quarterly and monthly distributions using records available at the Regional Veterinary Services (VS) Laboratory, Kumasi, Ghana from January 2018 to December 2021.

Methods     

Study location

The study was conducted at the Regional Veterinary Services Laboratory located at Amakom in the Kumasi Metropolitan Assembly of the Ashanti Region. Kumasi is the capital city of the Ashanti region of Ghana, and it is situated at the GPS Coordinates: 6.68422, -1.5793 (Longitude, Latitude) as shown in Figure 1 below; with a land area of 254 km² and a human population of about 4.43981 million, according to the 2021 Population and Housing Census [10]. Diagnosis of diseases at the Regional VS Laboratory, Kumasi was based on history provided by the poultry farmers, necropsy findings, and specific laboratory investigations. In some cases, specific laboratory investigations included culture, isolation and identification of pathogens.

Data collection

Required data on poultry diseases from January 2018 to December 2021 was extracted from laboratory records available at the Regional Veterinary Services Laboratory, Kumasi. The extracted data were regrouped into monthly, quarterly, and annual numbers of cases diagnosed.

Data analysis

The extracted data were entered, categorized, and analyzed using Microsoft Excel version 2019. Descriptive statistics were used to interpret the data in the form of frequencies, charts, and percentages.

Results     

Annual prevalence

A total of 6,747 necropsy cases of poultry diseases were diagnosed and documented at Regional VS Laboratory, Kumasi from January 2018 to December 2021. The annual, quarterly, and monthly figures are indicated in the proceeding tables. From Table 1, the total prevalence of respiratory disease recorded during the study period at the VS Laboratory, Kumasi was 29.61% (1998/6,747) and the annual prevalence of cases of respiratory diseases was highest in 2021, 32.05% (534/1666) followed by 2019 (30.42%), 2018 (29.25%) and 2020 (26.66%).

Quarterly prevalence

The quarterly distribution and prevalence of respiratory diseases in poultry during the study period are indicated in Table 2. The highest quarterly prevalence was recorded in the 3^rd quarter (31.86%, 503/1579) followed by 4^th quarter (31.32%, 514/1641), 2^nd quarter (28.00%, 504/1800) and 1^st quarter (27.62%, 477/1727).

Monthly prevalence

From Table 3, it is indicated that the highest prevalence of respiratory diseases in poultry on a cumulative monthly basis during the study period was recorded in November (34.27%), whilst the lowest was recorded in March (22.97%).

Prevalence of specific respiratory diseases of poultry

From Table 4, it has been established that Newcastle disease recorded the highest cumulative occurrence of 1289 (64.51% of respiratory diseases) of all respiratory diseases diagnosed during the study period, followed by CRD (chronic respiratory disease) of 389 (19.10% of respiratory diseases), whilst ILT recorded the lowest figure of 3 (0.15% of respiratory diseases).

Discussion     

Results obtained from this study indicate that, out of the total of 6,747 diseases of poultry recorded at the VS Laboratory in Kumasi during the study period, 1998 (29.61%) were cases of respiratory disease. This figure establishes the fact that the occurrence of respiratory diseases in poultry in the Ashanti of Ghana is high. Similar studies conducted by Boakye et al. [11] and Awuni et al. [12] showed that respiratory diseases were among the main causes of infections in poultry in Ghana.

Regarding quarterly prevalence, the study determined that the prevalence of respiratory diseases in poultry in the study area was highest in the 3^rd quarter (31.86%), whilst the lowest prevalence was recorded in the 1^st quarter (27.62%). A study previously conducted in Bangladesh by Badruzzaman et al. (2015), reported overall quarterly prevalence to be highest in the 2nd quarter (39.85%) followed by the 4th quarter (32.80%) and 3rd quarter (27.35%). The highest cumulative monthly prevalence of 34.27% in this current study was recorded in November, whilst the lowest (22.97%) was recorded in March. This may be associated with weather, in Ghana, this period falls within dry season and aerosol transmission is very important in respiratory disease hence aerosol transmission in the dry season may play significant role.

The current study determined the respiratory diseases recorded during the study period were Newcastle Disease (ND), Chronic Respiratory Disorder (CRD), Avian Influenza (AI), Aspergillosis (Asp), Infectious Coryza (IC) and Infectious Laryngotracheitis (IL). Previous researchers [11,12] reported the same diseases, except AI and IL, as the main respiratory diseases having a significant impact on the poultry industry in Ghana. Of the specific respiratory diseases recorded during the study period, ND had the highest cumulative prevalence (19.10%), followed by CRD (5.77%), whilst IL had the lowest (0.04%). Results from several previous studies [12, 13,14] supported the current finding of ND being the most frequently diagnosed respiratory disease of poultry. The high occurrence of Newcastle disease in poultry is mainly due to improper vaccination, inadequate cold chain, maternal antibodies interference and contact with local, wild and migratory birds which are not vaccinated but are disease-resistant [11,14].

Although vaccination schedule for poultry is the responsibility of the Veterinary Service Department in Ghana, the efficiency of the vaccination schedule was evaluated both for layers and guinea fowls and they were found to be adequate (15, 16), however farmers do not often follow the vaccination schedule strictly, coupled with poor biosecurity practices in many farms hence the high prevalence of respiratory diseases observed in poultry in the Ashanti region of Ghana. The limitation of the study includes the need to evaluate the poultry host range of the respiratory disease, role of migratory birds including water fowls and role of shedding of vaccine strain.

Conclusion     

The prevalence of respiratory diseases of poultry diagnosed at VS Laboratory, Kumasi is high (29.61%), hence could be considered as a major threat to the poultry industry. Newcastle disease, chronic respiratory disease, infectious coryza, avian influenza, and aspergillosis are the main respiratory diseases diagnosed during the study period (January 2018 to December 2021). Newcastle disease is the most prevalent respiratory disease recorded during the period followed by chronic respiratory disease. Improved education of poultry farmers and other stakeholders in the poultry industry on preventive and control measures could reduce the high prevalence of these diseases.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Raphael Deladem Folitse conceptualised the study and designed it. Data collection and analysis was performed by Raphael Deladem, Patrick Mensah Amponsah, Esther Amemor and Stephen Debrah. Writing of original manuscript was conducted by Raphael Deladem Folitse. Review and editing of the manuscript were performed by Stephen Debrah, Benjamin Obukowho Emikpe and Esther Amemor. The authors have read and agreed to the final manuscript.

Acknowledgments     

The authors wish to thank the leadership and workers at the Regional Veterinary Services Laboratory located at Amakom in the Kumasi Metropolitan Assembly of the Ashanti Region for their permission and availability in conducting this study.

Tables and figures     

Table 1: annual prevalence of respiratory diseases of poultry, diagnosed at VS Laboratory, Kumasi (2018-2021)

Table 2: quarterly distribution of respiratory diseases of poultry, diagnosed at VS Laboratory, Kumasi for each year (2018-2021)

Table 3: monthly distribution of respiratory diseases of poultry diagnosed at VS Laboratory, Kumasi, (2018-2021)

Table 4: annual cases of specific respiratory diseases in poultry diagnosed at VS Laboratory, Kumasi, from January 2018 to December 2021

Figure 1: map of Ghana indicating Ashanti region

References