Organs seizures at the slaughterhouse are safe public health approach. It removes animals or parts of animals that could be contaminated or at risk for human consumption. The procedures at the slaughterhouse are intended to protect public health in three steps: (1) ante-mortem inspection during which animals are examined prior to be slaughtered using symptoms of diseases and (2) post-mortem inspection, during which organs are examined after slaughter to detect abnormalities and (3) seizures of contaminated or abnormal organs removing them from the meat processing system. 

The criteria for recording data from seized organs include zoonotic diseases (e.g. tuberculosis, brucellosis, cysticercosis, fasciolosis, etc.) and abnormalities (e.g. tumours, abscesses, etc.). The seized organs are destroyed to remove them from human consumption an important measure to protect public health. Indeed, zoonoses are real risks and those such as cysticercosis, tuberculosis and fasciolosis can be transmitted from animals to humans, especially when there is an inappropriate meat inspection at the slaughterhouse. The consequences can be serious or even lethal for consumers of slaughtered products; meaning seizures through inspection procedures are crucial to protect public health. Livestock producers must be vigilant and respect herd management to minimize risks which can have devastating impact on human health. Based on these issues, strategies to prevent and control zoonoses are needed (Hayle et al., 2020). 

The purpose of this study was to assess the level of organs seizures associated to zoonoses as well as the year of inspection according to the historical data collected from 2018 and 2019. Finaly, to enable public and animal health sectors to set up a strategy for the prevention and control of the occurrence of transmitted zoonoses from animals to humans due to a weak inspection at the meat processing plant.

Scope of the study

The purpose of meat inspection is to protect public health by providing risk free products to the population. It also provides information that can be utilized for control of animal diseases (Gracy et al., 1999). Abattoir data is an excellent option for detecting diseases of both economic and public health importance. This study was conducted at the Refrigerated Slaughterhouse of Ouagadougou (AFO), the largest meat processing plant in Burkina Faso. The management of the slaughterhouse was entrusted to the Management office of the refrigerated slaughterhouse of Ouagadougou (SOGEAO) on 22 October 2004 by the Burkinabe State through a concession agreement. The slaughters carried out are monitored by sworn veterinarians from the Ministry of Agriculture, Animal Resources and Fisheries (MARAH) ensuring the meat inspection as well. 

Study Design 

The study was designed based on historical data from the slaughterhouse and the inspection records for the years 2018 and 2019 from the Ministry. The slaughtering of animals is mainly carried out on cattle, sheep, goats, pigs, sometimes donkeys and camels. Subsequent to the slaughter, organs including liver, lung, kidney, heart, and whole carcass were carefully examined by meat inspectors through palpation and incision to discover the evidence of diseases and other abnormalities which provided the data reported in the registers. From which registers, records were extracted for the purpose of this study using (Drago et al., 1994) guidelines.

Data processing and analysis

The data were extracted from MARAH's registers and statistical reports for the period of January 2018 to December 2019. The extraction was done exhaustively and compiled in Microsoft Excel tables covering all slaughter entries of the period. It also consisted of transforming the data compiled in the tables into readable data using the STATA 17 software thus, allowing easier analyses. Then, the descriptive analysis was carried out using Microsoft's Office 2021 Excel software and the logistic regression model fitted by STATA 17 software using the data. 

 Descriptive results

The Table 1 hereunder shows that tuberculosis (25.4%) and onchocerciasis cysts (21.1%) were the main reasons of seizures, followed by congestion (14.4%) and putrefaction (8.8%). Some lesions such as cachexia, cadaveric meat etc were absent.

Table 1: Distribution of the number of organs seized in ruminants (cattle, sheep, goats) at the refrigerated slaughterhouse of Ouagadougou from 2018 to 2019 (N=40379).

Table 2 hereunder showed about 30.1 per cent of seizures due to suspected zoonoses which is quite 

appreciable.

Table 2: Distribution of the number of organs seized linked to suspected zoonoses in ruminants (cattle, sheep, goats) subsequent to inspections at the refrigerated slaughterhouse of Ouagadougou from 2018 to 2019.

Table 3 showed that tuberculosis is most frequently suspected zoonoses. It accounts for (84.4%) of suspected zoonotic cases, followed by fasciolosis (9%) and cysticercosis (5.9%).

Table 3: Distribution of the number of organs seized among suspected cases of zoonoses in ruminants (cattle, sheep, goats) subsequent to inspections at the refrigerated slaughterhouse of Ouagadougou from 2018 to 2019.

Chi2 test of variables independency 

The Chi2 test of variable independence was made while hypothesizing and considering the existence of a significant association between seizures and zoonoses as a hypothesis to be retained. The test yielded Table 4 hereunder. The chi2 test showed an extremely low p-value, p< 0.0001 indicating that the probability of the observed differences is almost zero between the months and the different zoonoses. By rejecting the hypothesis of independence, the result revealed a significant association between months of the year and the suspected zoonoses.

Table 4: Monthly distribution of suspected zoonoses in ruminants (cattle, sheep, goats) subsequent to inspections at the refrigerated slaughterhouse of Ouagadougou from 2018 to 2019 (N= 12136)

Statistic Chi² = 1214.18; Degree of Freedom (df) = 68; p-value < 0.0001

The chi2 test performed with the data in Table 5 hereunder revealed a statistically significant association (χ² = 719.51; df = 8; p < 0.001) between seized organs with suspected zoonoses, indicating that the probability of detecting a zoonoses from seized organ is possible.

Table 5: Distribution of seized organs linked to suspected zoonoses in ruminants (cattle, sheep, goats) subsequent to inspections at the refrigerated slaughterhouse of Ouagadougou from 2018 to 2019.

¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Chi² Stat:  719.51; Degree of Freedom (df) = 8; p-value: 4.51 × 10⁻¹⁵⁰ 

The Chi² independence test revealed a statistically significant association between animal species and the occurrence of zoonoses (χ² = 921.07; df (2); p < 0.001). Cattle, goats and sheep have respectively different levels of association with zoonoses.

 

Table 6: Distribution of seizures by type of animal linked to a suspicion of zoonoses in ruminants (cattle, sheep, and goats).

Chi² Stat: 921.07; Degree of Freedom (df):  2; p-value: 9.82 × 10⁻²⁰¹ 

Logistic regression model

The study using the data fitted a logistic regression model using STATA 17 package hypothesizing that there is an association between animal species, seized organs, year of seizure and zoonoses, we end up with the results of Table 7 below. Indeed, the table showed that seizures of goat and sheep carcasses had a weak association with the occurrence of zoonoses. Their Odds Ratios (ORs) of OR=0.08 and OR=0.17 respectively with very low p-values, indicate that these associations, although weak, were significant and thus confirm that the risk is lower in these animal species. However, several organs showed important associations related to zoonoses, including cattle carcasses OR=2.69, hearts OR=1.13, livers OR=1.22, intestines OR=1.73 and lungs OR=1.21. Their p-values: p<0.0001, confirm the associations. On the other hand, spleens OR=0.24 and kidneys OR=0.25 were less associated with zoonoses, also confirmed with significant p-values p<0.0001. The year 2019 with an OR=1.33 is more associated with the risk of zoonoses than 2018. The p-value being very significant p<0.0001.