Identification and Prevalence of <i>Brucella</i> Species Circulating among Cattle Slaughtered in the Douala and Buea Municipalities of Cameroon

Eko, Seraphine Mojoko; Esemu, Seraphine Nkie; Njouendou, Abdel Jélil; Kfusi, Achah Jerome; Anong, Nota Damian; Ndip, Lucy Mande

doi:https://doi.org/10.1155/2023/2068948

Veterinary Medicine International

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Abstract Introduction Materials and Methods Results Discussion Conclusion Data Availability Conflicts of Interest Acknowledgments References Copyright Related Articles

Research Article | Open Access

Volume 2023 | Article ID 2068948 | https://doi.org/10.1155/2023/2068948

Identification and Prevalence of Brucella Species Circulating among Cattle Slaughtered in the Douala and Buea Municipalities of Cameroon

Seraphine Mojoko Eko,^1,2Seraphine Nkie Esemu,^2,3Abdel Jélil Njouendou,¹Achah Jerome Kfusi,²Nota Damian Anong,^2,4and Lucy Mande Ndip^2,3

Academic Editor: Carlos Viegas

Received14 Jan 2023

Revised09 Mar 2023

Accepted14 Mar 2023

Published10 Apr 2023

Abstract

Brucellosis is a neglected zoonotic disease affecting the livestock sector in low-income countries. Cameroon, a lower-middle-income country in sub-Saharan Africa, has reported the prevalence of brucellosis in regions where livestock rearing is the principal economic activity. However, the presence of the disease has not been reported in southern regions receiving cattle for consumption by their population. In addition, there is no report on the Brucella species circulating in Cameroon. This study aimed to determine the prevalence of brucellosis in cattle slaughtered in the Buea and Douala slaughterhouses and identify the Brucella species circulating among these animals. A total of 576 cattle serum samples were collected from the Buea and Douala slaughterhouses and analysed by ELISA. Following the ELISA assay, all samples were subjected to polymerase chain reaction (PCR) analysis. The bcsp31 gene primers were used for the genus-specific PCR. All bcsp31-positive samples were subjected to species-specific PCR. Primers targeting the IS711 gene sequence were used to identify the abortus-melitensis-ovis-suis species. The prevalence of brucellosis in both locations was 3.1% and 5.4% using the ELISA and PCR assays, respectively. Out of the 18 ELISA-positive samples, 5 (27%) were positive with PCR, while 26 (4.7%) of the ELISA-negative samples were positive with PCR. The Brucella species in circulation were identified using the Sanger sequencing technique. The sequences were 99.3% to 100% identical to the B. abortus strain BJ1-23 and the B. abortus strain BJ1-1 of the 31 kDa antigen (bcsp31) gene from India. This is the first report on the genotypic characterisation of Brucella species in Cameroon and confirms brucellosis in cattle at the Buea and Douala slaughterhouses.

1. Introduction

Brucellosis, caused by a group of bacteria of the genus Brucella, is a widespread, endemic, and neglected zoonotic disease in most low-income countries [1, 2]. The genus Brucella includes twelve species, some of which are host-specific [3, 4]. The disease affects both humans and domestic animals, particularly cattle [2, 5].

Cattle brucellosis is usually caused by B. abortus and occasionally by B. melitensis and B. suis [6]. The disease can be spread through several routes, including ingesting contaminated feed, water, or milk. It can also be spread through the suckling or licking of an infected placenta, newborn, foetus, or the genitalia of an infected female soon after it has been aborted or after birth [7]. This disease is associated with abortion, death of young ones, stillbirth, retained placenta, the birth of weak calves, delayed calving, male infertility, and a marked reduction in milk yield [8]. Consequently, it has a negative economic impact in low-resource settings where livestock is a source of food security and income [9]. Losses due to this disease are a direct result of abortions and the associated reduction in milk yield [10].

Brucellosis has been reported in 86 countries worldwide and is a serious threat to livestock and human health globally, with more than 500,000 documented livestock and human cases reported annually [8, 11]. Sporadic cases of cattle brucellosis are often reported in some sub-Saharan African countries, with prevalence reaching 41% in some areas [2, 5, 7]. Cattle brucellosis is endemic in Cameroon, with reported seroprevalence ranging from 2.3–30.8% [6, 10, 12–18]. A recent study investigating brucellosis in domestic animals reported an overall seroprevalence of 6.4%. Prevalence was highest in cattle (9.1%) followed by sheep (8.0%), dogs (6.1%), pigs (1.9%), and goats (1.1%) [2]. Cameroon, therefore, possesses sufficient livestock that can sustain the presence of multiple Brucella spp.

The management of animal brucellosis in Cameroon so far has been complex. This difficulty has been mainly due to the uncontrolled movement of diseased animals (mainly cattle) within and outside the national territory [6]. In addition, there is no surveillance system for detecting and slaughtering to eliminate infected cattle from the herds [4, 18]. A review of the literature on brucellosis research in Cameroon revealed that no study has been conducted in regions experiencing the urbanisation of cattle from the regions reported to be endemic for the disease [4, 18]. In Cameroon, only one attempt has been made at speciating Brucella in a study by Mitterran et al., who revealed a prevalence of 18.4% for B. abortus and 1.7% for B. melitensis in cattle [19]. Our study aimed to determine the prevalence of cattle brucellosis in the littoral and south-west regions of Cameroon, by investigating cattle slaughtered at the Buea and Douala slaughterhouses. This study also aimed to identify Brucella species circulating in the study areas. The species identification was done using the genus-specific PCR (targeting the 31 kDa Brucella antigen; bcsp31 gene), species-specific PCR (abortus-melitensis-ovis-suis PCR; AMOS-PCR), and Sanger sequencing.

2. Materials and Methods

2.1. Study Areas

This study investigated cattle slaughtered for meat in the Douala and Buea municipalities (Figure 1). Douala is the capital of the littoral region of Cameroon. It is the largest city in Cameroon.

With a population of about 3.9 million [20], and hosts one of the three industrial slaughterhouses in the country [21], this city is located in the monomodal forest zone, characterised by humid tropical evergreen forest, with gigantic trees, and periforest savannah [22]. This vegetation disfavours cattle rearing. Hence, the population in Douala and the neighbouring towns rely on cattle transported from the Adamawa, far north, north, northwest, and west regions of Cameroon as a food source. These cattle are sold at a popular cattle market in Bojongo, Douala.

Buea is a semiurban setting with a population of about 200,000 inhabitants [23]. It has two traditional slaughterhouses. The larger slaughterhouse, serving a greater proportion of its population, was selected for this study. Its population also relies on cattle from the country’s northern regions for beef. Cattle at this slaughterhouse are bought from the cattle market in Douala and transported to Buea.

2.2. Study Design and Period

This was a cross-sectional study that investigated serum samples from cattle slaughtered in the Douala and Buea municipalities in the littoral and southwest regions of Cameroon, respectively. These two regions of the country were selected because there is no documented evidence of cattle brucellosis in these regions. The lone slaughterhouse in Douala, where not less than 200 cattle are slaughtered daily, was used as a sample collection site. In Buea, samples were collected from the main slaughterhouse, where not more than five cattle are slaughtered daily, except on feast days. A total of six samples (one from Buea and five from Douala) were collected on each sample collection day. The samples from Buea were collected randomly, while the samples from Douala were collected based on a calculated sampling factor of five, every fifth cow on the chain was sampled before slaughtering. Sample collection was carried out for six months (September 2020 to February 2021).

2.3. Sample Size Estimation

The minimum sample size was calculated using the formula for a cross-sectional descriptive study assuming an unlimited population size [24]:where d is the absolute error or precision (estimated at 5%), z is the z-score of 1.96 for a 95% confidence interval, and is the expected proportion of the population based on previous studies [24].

2.4. Ethical Considerations

Administrative authorizations to carry out this study were obtained from the Regional Delegations of Livestock, Fisheries, and Animal Husbandry of the littoral (Ref No. 28/AR/DDEPIA-WOURI of 30th June, 2020) and the south west (Ref No. MINEPIA/RD/SRAG/SW/04/1099 of 5th August, 2020) regions. In addition, verbal authorizations were obtained from the Head of each slaughterhouse.

2.5. Blood Collection and Separation of Serum

From each cow, 5 mL of blood were collected by jugular venipuncture using a sterile vacutainer. Each tube was assigned a unique identification code. The blood samples were placed in a cool box containing icepacks with the temperature maintained at +4°C, and the cold chain was maintained during sample transportation. The temperature was monitored using a temperature data logger (Testo 174T, West Chester, USA). In the laboratory, each blood sample was centrifuged at 5000 rpm for 5 min to separate the serum from blood cells. About 1 mL of serum was harvested and transferred into clean 1.5 mL Eppendorf tubes. Serum samples were stored at −20°C until they were analysed. Overall, 576 blood samples were collected.

2.6. Collection of Epidemiological Data

The cattle were examined, and demographic data were obtained by trained veterinary staff at the slaughterhouses. A data collection sheet was used to record epidemiological data on cattle breeds, age, and sex. The age was estimated by dental inspection and inspection of horn rings for animals without teeth [17].

2.7. Detection of Anti-Brucella Antibodies Using an ELISA Assay

The indirect enzyme-linked immunosorbent assay (i-ELISA, DRG Instruments GmbH, Germany) was performed to detect the presence of antibodies against Brucella spp. according to the manufacturer’s instructions without any modifications. An automatic microplate reader (ERBA MANNHEIM Lisa Scan II) was used to measure optical density. For each sample, the ratio (S/) was calculated as follows:where OD_sample, OD_nc, and OD_pc are the readings of optical densities for the sample, negative control, and positive control, respectively. The samples were considered positive if the S/ ratio was ≥0.4 and negative if <0.4. The test was considered valid if the mean value of the measured OD for the positive control diluted 1 : 100 was ≥1.0 and the mean value for the negative control diluted 1 : 250 was ≤0.35.

2.8. DNA Extraction

DNA was extracted from all serum samples individually, using the QIAamp DNA Blood Kit (Qiagen, Hilden, Germany). The extraction was performed according to the manufacturer’s instructions without any modifications.

2.9. Amplification and Detection of Brucella Genus-Specific DNA

The identification of bacteria of the genus Brucella was performed using the B4/B5 primers (Table 1). All primers (Table 1) were synthesised at Inqaba Biotec (Inqaba Biotec, South Africa). PCR reactions were carried out in a final volume of 25 μL, comprising 12.5 μL of OneTaq 2X Master Mix (New England Biolabs, USA), 0.5 μL (from a 20 μM working solution) of each primer, 5 μL of DNA template, and nuclease-free water to make up the volume. Each PCR run included a positive control of B. abortus (vaccine strain) genomic DNA provided by Dr. Abel Wade, Director of the National Veterinary Laboratory (LANAVET), Yaounde, Cameroon. The PCR was performed in a MultiGene OptiMax Thermal Cycler (Labnet International, Edison, NJ, USA) under the following cycling conditions: initial denaturation at 95°C for 5 min followed by 40 cycles of amplification. Each cycle comprised denaturation at 95°C for 1 min, annealing at 52°C for 30 s, and extension at 72°C for 30 s. At the end of the 40th cycle, a final extension step was performed at 72°C for 5 min.

The presence or absence of the PCR product (223 bp) was determined by agarose gel electrophoresis (1.5%) at 80 V for 45 min. The gel was stained with SYBR Safe DNA Gel Stain (Invitrogen, Thermo Fisher Scientific, USA), and the DNA bands were visualised under UV illumination using the Gel Documentation-XR (BioRAD, Hercules, CA).

2.10. Identification of Brucella Species

All positive samples for the bcsp31 gene were subjected to the Brucella spp. PCR protocol targeting the IS711 gene. A multiplex PCR assay (AMOS-PCR) using a five-primer cocktail (Table 1), as previously described, was used [26–28]. The multiplex PCR mix comprised 5 μL template DNA, 0.5 μL of each of the forward and reverse primers (to give a final concentration of 0.4 μM), 12.5 μL of OneTaq 2X Master Mix (New England Biolabs, USA), and nuclease-free water to make up the volume. Both positive and negative controls were included in each PCR run. The PCR cycling conditions were the same as mentioned above, except for the number of cycles that was dropped to 35. Agarose gel electrophoresis was then performed to detect the presence or absence of the PCR product at 80 V for 45 min.

2.11. Differentiation between the B. abortus Wild-Type and the Vaccine Strains

A sixth primer within the IS711 sequence (Table 1) was added to the AMOS-PCR primer cocktail to differentiate between wild-type and vaccine strains of B. abortus. The RB51/2308 primer amplifies a 364-bp sequence which is not present in other wild-type Brucella spp. [29].

2.12. Sequencing and Analysis of PCR Products

Selected amplicons of the bcsp31 gene fragment were sequenced for further identification of bacterial spp. This selection was based on the robustness of the bands after electrophoretic separation. Sequencing was done in both directions for maximum data accuracy at Inqaba Biotech (Inqaba Biotech, South Africa).

Partial DNA sequences of reference Brucella spp. were retrieved from the NCBI GenBank database (https://www.ncbi.nlm.nih.gov/refseq/) for comparison with local DNA sequences of all Brucella spp. obtained in this study. The similarities between local sequences and reference strains were determined using the Basic Local Alignment Sequence Tool (BLAST) (https://blast.ncbi.nlm.nih.gov/Blast.cgi). Similarity matches between Brucella spp. reported in the study were determined in a pair-wise sequence alignment using BioEdit version 7.2.5. Multiple alignments of the nucleotide and amino acid sequences were carried out using Moleular Evolutionary Genetics Analysis (MEGA) version 11.

2.13. Data Analysis

Data were analysed using the Statistical Package for Social Sciences (SPSS) version 25. Data were described using frequency and proportion at 95% CI. The study indicators were compared among categories of demographic information using cross-tabulation and a test of association, notably the chi-squared test of equality of proportion. This bivariate association test depicted a significant association between two variables.

3. Results

3.1. Cattle Demographic Characteristics

Blood samples were collected from 576 cattle: 465 (80.7%) from Douala and 111 (19.3%) from Buea. The majority of the cattle (77.6%) were matured, and there were more male (96.9%) than female cattle (3.1%). The most predominant breed was the White Fulani/Akou (40.8%), followed by the Red Fulani/Djafoun (27.1%) and Goudali (25.2%) (Table 2).

All cattle slaughtered at the slaughterhouses in Douala and Buea were purchased from the Douala cattle market. In 2020, this cattle market received a total of 62,203 cattle, originating from seven regions of the country. The highest number of cattle were from the north region (42%), the far north (35%), and Adamawa regions (15%) (Figure 2).

3.2. Seroprevalence of Cattle Brucellosis

The overall brucellosis seroprevalence was 3.1% (95% CI: 1.9–4.9). Of the 111 cattle from Buea, only one (0.9%, 95% CI: 0.02–4.9) had anti-Brucella antibodies. Of the 465 cattle from Douala, 17 (3.7%, 95% CI: 2.1–5.8) also had anti-Brucella antibodies (Table 3). However, the difference in prevalence between the two collection sites was not statistically significant ( value = 0.134). Prevalence according to sex was 11.1% for female cattle, 3.5% for males, and no infection amongst the castrated cattle. There was no discernible difference in predominance between breeds.

3.3. Prevalence of Cattle Brucellosis Using PCR

The genus-specific PCR targeting a fragment of the 31 kDa surface protein amplified DNA segments of molecular weight, 223 bp (Figure 3). The bcsp31 gene was detected in 5.4% (95% CI: 3.7–7.6) of the samples (Table 3). The highest infection rates were recorded amongst the bulls (5.9%), matured cattle (5.8%), and cattle from Douala (6.0%). Based on the breed, more infections were seen amongst the White Fulani (6.0%), followed by the Red Fulani (5.1%).

3.4. Correlation between the ELISA and PCR Results

The overall prevalence of brucellosis based on ELISA was 3.1%, while based on genus-specific PCR, it was 5.4% (Table 3). Out of the 18 ELISA-positive samples, 5 (27.8%) were confirmed positive by PCR, while 13 (72.2%) were PCR negative (Table 4). Of the 558 ELISA-negative samples, 26 (4.7%) were PCR positive, while 532 (95.3%) were PCR negative. The difference in results based on PCR and ELISA assays was statistically significant (-value ≤0.001).

3.5. Identifying Brucella Species in Cattle

The AMOS-PCR was performed on all 31 samples that were positive for the bcsp31 gene. The four primer pairs failed to amplify any of the species in the samples. The assays were validated by the amplification of the positive control (B. abortus vaccine strain) that produced a 498 bp band during each PCR run. Singleplex reactions were performed using each primer pair, and the same results were obtained. Additional primers were used to distinguish the wild type from the vaccine strains. In this reaction, only the positive control amplified a 364 bp DNA segment corresponding to the vaccine strain. Hence, the samples in this study contained only the wild type and not the vaccine strains.

3.6. Nucleotide Sequence Analyses of the Brucella bcsp31 Gene

Selected amplicons of the bcsp31 gene segment were sequenced and analysed. At the nucleotide level, the bcsp31 gene of the 9 DNA samples had sequence identities ranging from 99.3 to 100% to each other and the reference sequence (Table 5). The BLAST of these sequences revealed homologies of 99.38 to 100% to the B. abortus strain BJ1-23 reference sequence (https://www.ncbi.nlm.nih.gov/nucleotide/MK240100.1?report=genbank&log$=nucltop&blast_rank=1&RID=N37SJSN4013), and the B. abortus strain BJ1-1 reference sequence (https://www.ncbi.nlm.nih.gov/nucleotide/MK240101.1?report=genbank&log$=nucltop&blast_rank=10&RID=N4JH7HKH016) from India (Table 6). The sequences for eight samples showed 100% homology to each other and the reference sequences. These eight identical sequences comprised four samples from Douala (CMR_DC302, CMR_DC313, CMR_DC40, and CMR_DC182), and four samples from Buea (CMR_BC56, CMR_BC23, CMR_BC31, and CMR_BC54). The sample CMR_DC243 (from Douala) showed 99.3% homology to the local and reference sequences. This difference observed between the sequences was the absence of a nucleotide at position 47 (Figure 4).

4. Discussion

Cameroon possesses sufficient livestock, including cattle, pigs, goats, and sheep, which have the potential to sustain the presence of multiple Brucella spp. [18]. These animals serve as sources of food, which are an essential part of the diet of the Cameroonian population [30]. Brucellosis is more of a disease of cattle than any other animals [2]. This sentence has been rephrased to “This justifies the use of cattle for this study.” Buea and Douala, the sample collection sites, are towns with minimal cattle-rearing activity. Most of the cattle slaughtered for food in these towns migrated from the country’s northern regions, where the disease is reported to be endemic. Hence, the presence of brucellosis in these cattle is a risk factor for the spread of brucellosis to humans and other animals at these locations.

More samples were collected from Douala than from Buea because Douala has an industrial slaughterhouse with a slaughter capacity that is more than 10 times that of Buea. For instance, before the COVID-19 pandemic, up to about 250 cattle were slaughtered daily in Douala [21]. However, these numbers decreased greatly during our study period. The demographic data of the cattle (the majority being matured, and more bulls than cows) are in line with regulations governing the slaughter of cattle in Cameroon. This regulation is stated in Article 17 of Decree No. 76/420 of September 1976, modified by Decree No. 86/755 of 24th June, 1986. The law forbids the slaughter of female cattle under 10 years of age, and male cattle below four years, except in cases of accidents, sterility, or incurable diseases certified by a veterinary officer [31]. Although the difference in the prevalence according to sex was statistically significant (), this can be ignored because of the bias in the slaughter of female cattle. This is, therefore, not an accurate representation of the prevalence of the disease in female cattle.

The cattle population investigated in this study differed from that of Awah-Ndukum et al. (2018), who studied a cattle population in the Ngaoundere slaughterhouse. Their study analysed more cows (89.6%) than bulls (10.4%). Up to 10% of their cattle population was less than four years old. This difference could be due to the fact that Ngaoundere is a significant cattle rearing area in Cameroon and may have a population of cattle that were not thriving, such as the young and sterile females that could be sold for slaughter. On the contrary, animals sent to the cattle market in Douala travelled long distances and are expected to arrive with good body scores in order to be sold for slaughter.

Seroprevalence studies have reported higher seroprevalence values in Cameroon, including 9.2% (i-ELISA) from parts of the west and central regions [2], 3.4–5.9% (RBPT and i-ELISA, respectively) in cattle in Ngaoundere [17], 4.6% (RBPT) in the western highland savannah [16], and 5.2% (c-ELISA) in the northwest region [7]. The higher prevalence in these regions could be attributed to agricultural practices, predominated by the rearing of livestock. In these regions, practice of transhumance on most of the farms was a risk factor for infection [6]. Migratory herds get in contact with other potentially infected herds during their movement, increasing the risk of infection [7]. The differences in prevalence could also be attributed to the use of different serologic assays and the differences in the sample collection sites (some at slaughterhouses and others on farms). These factors explain the difficulty in harmonizing the results from various study sites [18].

The higher prevalence of brucellosis using PCR (5.4%) compared to ELISA (3.1%) could be explained by the ability of the PCR method to detect infection at initial stages, before antibody production [32]. It also detects DNA, which is present in both living and dead Brucella organisms [33]. The PCR test is therefore important in cases where animals present with brucellosis clinically and serological tests are negative, allowing the rapid confirmation of the brucellosis [33].

The AMOS-PCR, commonly used for identifying species in the genus Brucella, did not identify any species in our study. This may be an indication of the great diversity of Brucella spp. circulating in this study area. It has been reported that the AMOS-PCR does not identify all biovars of the four target species. It identifies only three B. abortus biovars, 1, 2, and 4; all three biovars of B. melitensis; and biovar 1 of B. suis and B. ovis [27, 34, 35]. In the United States of America, this method was considered sufficient for identification of Brucella, since these biovars were typically being isolated from its local livestock [27]. Hence, there is a need to employ other approaches in speciating the bacteria in our study population.

Sequence analysis of the bcsp31 gene locus revealed that the nine amplicons represented Brucella strains that share 99.38 to 100% identity with B. abortus strain BJ1-23 and B. abortus strain BJ1-1 reference sequences from India. This is the first report on the sequencing of Brucella spp. in Cameroon, and it is essential to understand the genetic diversity of the pathogen in order to control the disease.

The strains in this study were not vaccine strains because they did not amplify the 364 bp DNA segment of the vaccine strain [27]. Likewise, they were not B. melitensis, considering the fact that the AMOS-PCR amplifies all biovars of B. melitensis [27]. This could imply that the species in circulation are more diverse than those detected by the AMOS-PCR. Hence, we recommend other molecular methods, such as the real-time PCR and the multiple locus variable-number tandem repeat analysis be used for further speciation [27, 36, 37].

It was impossible to trace the origin of individual cattle to the herds as there was no cattle identification system. Identification systems for cattle are critical in tracing the source of the infection, tailoring interventions, and tracking prevalence within the area [38]. An established tracking system will foster the implementation of the test-and-slaughter approach in controlling the infection [39, 40]. The culling of animals, however, is challenging in resource-poor countries due to the mobile pastoral systems and lack of proper compensation for herders [39]. It is advised that economic sustainability should always be considered before investing resources in the prevention and control of brucellosis [18]. The species of Brucella implicated in natural infections must not only be detected but also identified. Because brucellosis is a zoonotic disease, the fight against it in humans and animals is centred on veterinary sanitation measures aimed at reducing or eliminating the disease in farm animals [33].

5. Conclusion

This study was conducted to determine the prevalence of brucellosis in cattle slaughtered in the Buea and Douala slaughterhouses and identify the Brucella species circulating among these animals. The prevalence of brucellosis in both slaughterhouses was 3.1% and 5.4% using the ELISA and PCR assays, respectively. The sequences were 99.3% to 100% identical to the B. abortus strain BJ1-23 and the B. abortus strain BJ1-1 of the 31 kDa antigen (bcsp31) gene from India. This report confirms Brucella infections in cattle slaughtered at the Buea and Douala slaughterhouses. It is the first report on the genotypic characterisation of Brucella species in Cameroon. Further studies are needed to identify the strain diversity in this setting.

Data Availability

All data generated or analysed during this study are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Acknowledgments

The authors would like to acknowledge the Laboratory for Emerging Infectious Diseases, University of Buea, Cameroon, for the facilities put at their disposal for the realization of this project.

References

F. G. Bakri, H. M. Alqadiri, and M. H. Adwan, “The highest cited papers in brucellosis: identification using two databases and review of the papers’ major findings,” BioMed Research International, vol. 2018, Article ID 9291326, 10 pages, 2018.
View at: Publisher Site | Google Scholar
R. M. N. Kamga, B. A. Silatsa, O. Farikou, J. R. Kuiate, and G. Simo, “Detection of Brucella antibodies in domestic animals of southern Cameroon: implications for the control of brucellosis,” Veterinary Medicine and Science, vol. 6, no. 3, pp. 410–420, 2020a.
View at: Publisher Site | Google Scholar
S. Paul, B. V. Peddayelachagiri, M. Gogoi et al., “Genome-wide unique insertion sequences among five Brucella species and demonstration of differential identification of Brucella by multiplex PCR assay,” Scientific Reports, vol. 10, no. 1, p. 6368, 2020.
View at: Publisher Site | Google Scholar
S. M. Eko, S. N. Esemu, A. D. Nota, and L. M. Ndip, “A review on brucellosis in Cameroon: diagnostic approaches, epidemiology and risk factors for infection,” Advances in Microbiology, vol. 12, no. 07, pp. 415–442, 2022.
View at: Publisher Site | Google Scholar
R. M. N. Kamga, B. S. Assongo, E. M. K. Magang et al., “Seroprevalence of Brucella antibodies and risk factors associated with human brucellosis in high-risk occupational groups of the noun division in the West region of Cameroon,” Journal of Biosciences and Medicines, vol. 09, no. 03, pp. 105–123, 2021.
View at: Publisher Site | Google Scholar
J. Awah-Ndukum, M. M. M. Mouiche, H. N. Bayang et al., “Seroprevalence and associated risk factors of brucellosis among indigenous cattle in the Adamawa and North regions of Cameroon,” Veterinary Medicine International, vol. 2018, Article ID 3468596, 10 pages, 2018.
View at: Publisher Site | Google Scholar
P. H. Bayemi, G. D. Mah, K. Ndamukong et al., “Bovine brucellosis in cattle production systems in the western highlands of Cameroon,” International Journal of Animal Biology, vol. 1, no. 2, pp. 38–44, 2015.
View at: Google Scholar
M. Z. Khan and M. Zahoor, “An overview of brucellosis in cattle and humans, and its serological and molecular diagnosis in control strategies,” Tropical medicine and infectious disease, vol. 3, no. 2, p. 65, 2018.
View at: Publisher Site | Google Scholar
M. Carugati, H. M. Biggs, M. J. Maze et al., “Incidence of human brucellosis in the Kilimanjaro Region of Tanzania in the periods 2007-2008 and 2012-2014,” Transactions of the Royal Society of Tropical Medicine and Hygiene, vol. 112, no. 3, pp. 136–143, 2018.
View at: Publisher Site | Google Scholar
I. Musallam, A. P. Ndour, D. Yempabou et al., “Brucellosis in dairy herds: a public health concern in the milk supply chains of West and Central Africa,” Acta Tropica, vol. 197, Article ID 105042, 2019.
View at: Publisher Site | Google Scholar
E. R. Harrison and R. Posada, “Brucellosis,” Pediatrics in Review, vol. 39, no. 4, pp. 222–224, 2018.
View at: Publisher Site | Google Scholar
P. H. Bayemi, E. C. Webb, M. V. Nsongka, H. Unger, and H. Njakoi, “Prevalence of Brucella abortus antibodies in serum of Holstein cattle in Cameroon,” Tropical Animal Health and Production, vol. 41, no. 2, pp. 141–144, 2009.
View at: Publisher Site | Google Scholar
F. Scolamacchia, I. G. Handel, E. M. Fèvre et al., “Serological patterns of brucellosis, leptospirosis and Q fever in Bos indicus cattle in Cameroon,” PLoS One, vol. 5, no. 1, p. 8623, 2010.
View at: Publisher Site | Google Scholar
B. W. Ojong, “Situation of brucellosis in beef-type cattle raised under different husbandry systems in Cameroon. Establishment of a multi-sectorial strategy for the control of brucellosis in the main peri-urban dairy production zones of West and Central Africa Project Outline,” DAKAR, vol. 18, p. 2011, 2015.
View at: Google Scholar
A. T. Kong, M. V. Nsongka, I. Leinyuy, S. M. Itoe, and A. T. Hako, “Seroprevalence of Brucella abortus in the bamenda municipal abattoir of the western highlands, of Cameroon,” Greener Journal of Agricultural Sciences, vol. 6, no. 8, pp. 245–251, 2016.
View at: Publisher Site | Google Scholar
A. Vokaty, R. Thomas, S. Ahmed et al., “Leptospirosis in the caribbean: a one health approach,” International Journal of Infectious Diseases, vol. 53, pp. 63-64, 2016.
View at: Publisher Site | Google Scholar
J. Awah-Ndukum, M. M. M. Mouiche, L. Kouonmo-Ngnoyum et al., “Seroprevalence and risk factors of brucellosis among slaughtered indigenous cattle, abattoir personnel and pregnant women in Ngaoundéré, Cameroon,” BMC Infectious Diseases, vol. 18, no. 1, pp. 611–613, 2018.
View at: Publisher Site | Google Scholar
C. G. Laine, A. Wade, H. M. Scott, R. C. Krecek, and A. M. Arenas-Gamboa, “Scoping review of brucellosis in Cameroon: where do we stand, and where are we going?” PLoS One, vol. 15, no. 9, Article ID e0239854, 2020.
View at: Publisher Site | Google Scholar
K. N. R. Mitterran, S. A. Barberine, F. Oumarou, and G. Simo, “Detection of Brucella abortus and Brucellla melitensis in cattle and sheep from southern Cameroon,” Research square, pp. 1–13, 2020b.
View at: Publisher Site | Google Scholar
N. D. Noukeu, D. Enyama, G. N. Kofane et al., “Determinants of neonatal mortality in a neonatology unit in a referral hospital of Douala,” Health Sciences And Disease, vol. 22, no. 10, pp. 99–104, 2022.
View at: Google Scholar
Sodepa, “Rapports Annuel d’activités et de performance 2017. Yaounde, Cameroon,” 2017, https://www.sodepa.cm/wp-content/uploads/2019/08/Rapports-dactivités-et-de-performance-2017-.pdf.
View at: Google Scholar
Minader, “The state of Cameroon’S biodiversity for food and agriculture,” 2015, http://www.fao.org/3/CA3431EN/ca3431en.pdf.
View at: Google Scholar
C. Nkoke, A. M. Jingi, J. J. Noubiap et al., “Gender differences in cardiovascular risk factors , clinical presentation , and outcome of patients admitted with a hypertensive crisis at the Buea regional hospital , Cameroon,” International Journal of Hypertension, vol. 2022, Article ID 3062526, 6 pages, 2022.
View at: Publisher Site | Google Scholar
J. Charan and T. Biswas, “How to calculate sample size for different study designs in medical research?” Indian Journal of Psychological Medicine, vol. 35, no. 2, pp. 121–126, 2013.
View at: Publisher Site | Google Scholar
K. Mohseni, R. Mirnejad, V. Piranfar, and S. Mirkalantari, “A comparative evaluation of ELISA, PCR, and serum agglutination tests for diagnosis of Brucella using human serum,” Iran J Pathol, vol. 12, no. 4, pp. 371–376, 2017.
View at: Publisher Site | Google Scholar
M. M. Gumaa, Z. Li, X. Cao et al., “Specific detection and differentiation between Brucella melitensis and Brucella abortus by a duplex recombinase Polymerase amplification assay,” Frontiers in Veterinary Science, vol. 7, pp. 539679–539713, 2020.
View at: Publisher Site | Google Scholar
B. Kurmanov, D. Zincke, W. Su et al., “Assays for identification and differentiation of Brucella species: a review,” Microorganisms, vol. 10, no. 8, pp. 1584–1623, 2022.
View at: Publisher Site | Google Scholar
M. J. Saavedra, C. Fernandes, and C. Queiroga, “Laboratory diagnosis of brucellosis,” Brucellosis in Goats and Sheep, vol. 33, no. 1, pp. 151–180, 2019.
View at: Google Scholar
B. J. Bricker and S. M. Halling, “Enhancement of the Brucella AMOS PCR assay for differentiation of Brucella abortus vaccine strains S19 and RB51,” Journal of Clinical Microbiology, vol. 33, no. 6, pp. 1640–1642, 1995.
View at: Publisher Site | Google Scholar
R. V. Ngom, V. D. P. Ndzana, D. Bohounbele, V. Houli, B. Oumara, and A. Z. Pagnah, “Nutritional quality of meat from cattle breed in livestock production area of Cameroon,” Open Journal of Animal Sciences, vol. 12, no. 03, pp. 467–483, 2022.
View at: Publisher Site | Google Scholar
C. Ndi, N. E. Tambi, and N. W. Agharih, “Reducing calf wastage from the slaughtering of pregnant cows in Cameroon,” World review animal, vol. 4, no. 77, 1993, https://www.fao.org/3/v1650t/v1650t0g.htm.
View at: Google Scholar
S. K. Khurana, A. Sehrawat, R. Tiwari et al., “Bovine brucellosis-a comprehensive review,” Veterinary Quarterly, vol. 41, no. 1, pp. 61–88, 2021.
View at: Publisher Site | Google Scholar
S. Saadat, J. Mardaneh, M. Ahouran et al., “Diagnosis of cattle brucellosis by PCR and serological methods: comparison of diagnostic tests,” Biomedical and Pharmacology Journal, vol. 10, no. 02, pp. 881–888, 2017.
View at: Publisher Site | Google Scholar
M. B. Ledwaba, C. Gomo, K. E. Lekota et al., “Molecular characterization of Brucella species from Zimbabwe,” PLoS Neglected Tropical Diseases, vol. 13, no. 5, Article ID e0007311, 2019.
View at: Publisher Site | Google Scholar
G. Matope, E. Bhebhe, J. B. Muma, E. Skjerve, and B. Djønne, “Characterization of some Brucella species from Zimbabwe by biochemical profiling and AMOS-PCR,” BMC Research Notes, vol. 2, pp. 261–266, 2009.
View at: Publisher Site | Google Scholar
J. M. Winchell, B. J. Wolff, R. Tiller, M. D. Bowen, and A. R. Hoffmaster, “Rapid identification and discrimination of Brucella isolates by use of real-time PCR and high-resolution melt analysis,” Journal of Clinical Microbiology, vol. 48, no. 3, pp. 697–702, 2010.
View at: Publisher Site | Google Scholar
N. H. Abdel-Hamid, E. M. El-bauomy, H. M. Ghobashy, and A. A. Shehata, “Genetic variation of Brucella isolates at strain level in Egypt,” Veterinary Medicine and Science, vol. 6, no. 3, pp. 421–432, 2020.
View at: Publisher Site | Google Scholar
S. Smith, R. Koech, D. Nzorubara et al., “Connected diagnostics: linking digital rapid diagnostic tests and mobile health wallets to diagnose and treat brucellosis in Samburu, Kenya,” BMC Medical Informatics and Decision Making, vol. 19, no. 1, pp. 139–212, 2019.
View at: Publisher Site | Google Scholar
Y. B. Kanouté, B. G. Gragnon, C. Schindler, B. Bonfoh, and E. Schelling, “Epidemiology of brucellosis, Q Fever and Rift Valley Fever at the human and livestock interface in northern Côte d’Ivoire,” Acta Tropica, vol. 165, pp. 66–75, 2017.
View at: Publisher Site | Google Scholar
J. B. Ntirandekura, L. E. Matemba, S. I. Kimera, J. B. Muma, and E. D. Karimuribo, “Association of brucellosis with abortion prevalence in humans and animals in Africa: a review,” African Journal of Reproductive Health, vol. 22, no. 3, pp. 120–136, 2018.
View at: Publisher Site | Google Scholar

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Copyright © 2023 Seraphine Mojoko Eko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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