Temporal Analysis and Costs of Ruminant Brucellosis Control Programme in Egypt Between 1999 and 2011

New insights into the genetic predisposition of brucellosis and its effect on the gut and vaginal microbiota in goats

Goats contribute significantly to the global food security and industry. They constitute a main supplier of meat and milk for large proportions of people in Egypt and worldwide. Brucellosis is a zoonotic infectious disease that causes a significant economic loss in animal production. A case-control genome-wide association analysis (GWAS) was conducted using the infectious status of the animal as a phenotype. The does that showed abortion during the last third period of pregnancy and which were positive to both rose bengal plate and serum tube agglutination tests, were considered as cases. Otherwise, they were considered as controls. All animals were genotyped using the Illumina 65KSNP BeadChip. Additionally, the diversity and composition of vaginal and fecal microbiota in cases and controls were investigated using PCR-amplicone sequencing of the V4 region of 16S rDNA. After applying quality control criteria, 35,818 markers and 66 does were available for the GWAS test. The GWAS revealed a significantly associated SNP (P = 5.01 × 10-7) located on Caprine chromosome 15 at 29 megabases. Four other markers surpassed the proposed threshold (P = 2.5 × 10-5). Additionally, fourteen genomic regions accounted for more than 0.1% of the variance explained by all genome windows. Corresponding markers were located within or in close vicinity to several candidate genes, such as ARRB1, RELT, ATG16L2, IGSF21, UBR4, ULK1, DCN, MAPB1, NAIP, CD26, IFIH1, NDFIP2, DOK4, MAF, IL2RB, USP18, ARID5A, ZAP70, CNTN5, PIK3AP1, DNTT, BLNK, and NHLRC3. These genes play important roles in the regulation of immune responses to the infections through several biological pathways. Similar vaginal bacterial community was observed in both cases and controls while the fecal bacterial composition and diversity differed between the groups (P < 0.05). Faeces from the control does showed a higher relative abundance of the phylum Bacteroidota compared to cases (P < 0.05), while the latter showed more Firmicutes, Spirochaetota, Planctomycetota, and Proteobacteria. On the genus level, the control does exhibited higher abundances of Rikenellaceae RC9 gut group and Christensenellaceae R-7 group (P < 0.05), while the infected does revealed higher Bacteroides, Alistipes, and Prevotellaceae UCG-003 (P < 0.05). This information increases our understanding of the genetics of the susceptibility to Brucella in goats and may be useful in breeding programs and selection schemes that aim at controlling the disease in livestock.

Bayesian Evaluation of Three Serological Tests for Diagnosis of Brucella infections in Dromedary Camels Using Latent Class Models

Brucellosis is a zoonotic disease with significant economic and public health impacts. The disease has been found in ruminants, including camels, but clinical diagnosis of camel brucellosis is difficult due to the lack of clinical signs. Thus, this study aimed to estimate the sensitivity (Se) and specificity (Sp) of the Buffered Plate Antigen Test (BPAT), Rose Bengal Test (RBT), and indirect ELISA (i-ELISA) for the diagnosis of Brucella infection in dromedary camels imported from Sudan to Egypt. The secondary objective of the study was to calculate the animal-level true prevalence of Brucella infection in imported camels. A cross-sectional study was carried out on 921 apparently healthy camels randomly selected from those imported from Sudan and kept in the quarantine stations in the Shalateen area of the Red Sea Governorate, Egypt, between June 2018 and January 2019. Serum samples were collected and analyzed using BPAT, RBT, and i-ELISA. The posterior estimates [medians and 95% Bayesian probability intervals (95% BPI)] for Se and Sp of the three serological tests were obtained using Bayesian latent class models (BLCMs). The BLCM was fitted with the assumption that the BPAT and RBT tests were conditionally dependent on the true brucellosis status of camels. All tests had comparable and high Se (>86%) and Sp (>98%). The animal-level true prevalence of Brucella infection in imported camels was 8.6% (95% BPI: 6.8 - 10.7). Based on these findings, the three assays could be used for the initial screening of Brucella infection in camels. However, the BPAT and RBT are more suitable for use in camel brucellosis control and eradication program in Egypt because of their low unit cost and fast turnaround time compared to the i-ELISA. In addition, BPAT and RBT could be performed in the field where in-vivo tests are rarely used due to logistic and management constraints.

Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt

Brucellosis is a highly contagious zoonosis that occurs worldwide. Whole-genome sequencing (WGS) has become a widely accepted molecular typing method for outbreak tracing and genomic epidemiology of brucellosis. Twenty-nine Brucella spp. (eight B. abortus biovar 1 and 21 B. melitensis biovar 3) were isolated from lymph nodes, milk, and fetal abomasal contents of infected cattle, buffaloes, sheep, and goats originating from nine districts in Egypt. The isolates were identified by microbiological methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Differentiation and genotyping were confirmed using multiplex PCR. Illumina MiSeq^® was used to sequence the 29 Brucella isolates. Using MLST typing, ST11 and ST1 were identified among B. melitensis and B. abortus, respectively. Brucella abortus and B. melitensis isolates were divided into two main clusters (clusters 1 and 2) containing two and nine distinct genotypes by core-genome SNP analysis, respectively. The genotypes were irregularly distributed over time and space in the study area. Both Egyptian B. abortus and B. melitensis isolates proved to be genomically unique upon comparison with publicly available sequencing from strains of neighboring Mediterranean, African, and Asian countries. The antimicrobial resistance mechanism caused by mutations in rpoB, gyrA, and gyrB genes associated with rifampicin and ciprofloxacin resistance were identified. To the best of our knowledge, this is the first study investigating the epidemiology of Brucella isolates from livestock belonging to different localities in Egypt based on whole genome analysis.

Trans-species transmission of Brucellae among ruminants hampering brucellosis control efforts in Egypt

AIMS

This study aimed to identify the genotypic fingerprinting of Brucella melitensis biovar 3 isolates from ruminants in Kafr El-Sheikh, Egypt, to compare with other peers globally and to highlight the epidemiology and potential causes of brucellosis control failure.

METHODS AND RESULTS

A multilocus variable-number tandem-repeat analysis (MLVA 16) was carried out on 41 B. melitensis bv3 isolates, 31 from the preferential hosts (28 sheep and three goats) and 10 from atypical hosts (nine cattle and one buffalo), identified by bacteriological and molecular techniques. MLVA-16 analysis revealed 19 genotypes with nine as singletons. The most prevalent genotypes were M3_K.E (3,5,3,13,1,1,3,3,7,43,8,7,6,7,5,3), M13_K.E (3,5,3,13,1,1,3,3,7,43,8,5,8,7,7,3) and M5_K.E (3,5,3,13,1,1,3,3,7,43,8,4,8,7,11,3) circulating between different animal species. The B. melitensis isolation from aborted cows in farms that had never reared small ruminants indicates the likelihood of cow to cow B. melitensis transmission. Different genotypes of B. melitensis could be isolated from the same animal. The local geographic distribution of genotypes showed a very close genetic relatedness with genotypes reported outside the study area. Worldwide, our genotypes were mostly related to the Western Mediterranean lineage and less likely to the America's clonal lineage.

CONCLUSION

There is a high genetic similarity of B. melitensis bv3 genotypes among different ruminant species, and the same animal could be infected with different genotypes. There is a high probability of spreading of B. melitensis among atypical hosts in the absence of the original hosts. The genetic relatedness of B. melitensis bv3 genotypes in the study area with other different geographic areas highlighted the national and international ruminants movement role as a potential factor for maintaining B. melitensis infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

Further investigations are required to understand the impact of the presence of more than one genotype of B. melitensis in the same animal on the efficacy of brucellosis control strategies.

Seroprevalence and Molecular Identification of Brucella spp. in Camels in Egypt

Brucellosis is one of the most important worldwide zoonoses of many countries including Egypt. Camel brucellosis has not gained much attention in Egypt yet. This study is focused on the three governorates with the highest camel populations and the largest camel markets in the country to determine the disease seroprevalence and identify the Brucella species in local camel holdings. In total, 381 serum samples were collected from male and female camels from Giza, Aswan, and Al-Bahr Al-Ahmar (the Red Sea) governorates. Samples were serologically examined using the Rose-Bengal plate test (RBPT), indirect ELISA (i-ELISA), competitive ELISA (c-ELISA) and complement fixation test (CFT). Brucella antibodies were detected in 59 (15.5%), 87 (22.8%), 77 (20.2%) and 118 (31.0%) of sera by RBPT, i-ELISA, c-ELISA and CFT, respectively. Using real-time PCR, Brucella DNA was amplified in 32 (8.4%) seropositive samples including Brucella abortus (25/32), Brucella suis (5/32) and Brucella melitensis (2/32), defining a complex epidemiological status. To the best of our knowledge, this is the first study reporting Brucella suis DNA in camel serum. The risk-associated factors including age, sex, breed and geographical distribution were statistically analyzed, showing non-significant association with seroprevalence. The results of this study will raise awareness for camel brucellosis and help develop effective control strategies.

Socio-economic impacts of brucellosis on livestock production and reproduction performance in Koibatek and Marigat regions, Baringo County, Kenya

Background

Brucellosis in Africa is caused by Brucella species transmitted through contaminated or contacts with infected animals or their carcasses. The disease reduces livestock production and reproduction performance evident by frequent episodes of abortion, still births, swollen testes, weak calves/lambs and swollen joints. However, the socio-economic impacts of these brucellosis-associated symptoms on milk, fat, meat and blood production, infertility, sale value, dowry and costs of treatment has not been evaluated extensively in developing countries. In Baringo County, Kenya, there is a continuous movement of cattle as a result of trade and grazing, which predisposes many herds to brucellosis infection. The objective of this study was to investigate the socio-economic impacts of Brucella infection on production systems for sheep, goats, cattle and camels and explore the impact of brucellosis on livestock production and reproduction performance among livestock keeping communities in Baringo County, Kenya. The study adopted a cross-sectional survey using quantitative data collection methods.

Results

Results demonstrated an impact on milk production in suspected brucellosis cases resulting from abortions (OR = 0.151, P < 0.0001) and swollen joints (OR = 2.881, P < 0.0001). In terms of infertility, abortion as a symptom of brucellosis (OR = 0.440, P = 0.002), still birth (OR = 0.628, P = 0.042), and weak calf or lamb (OR = 0.525, P = 0.005) had an impact on infertility. In terms of sale value, abortion (OR = 0.385, P = 0.008), weak calf/lamb (OR = 2.963, P = 0.013) had an impact on sale value. Other analyses demonstrated that for dowry, swollen testes (OR = 5.351, P = 0.032), weak calf and lambs (OR = 0.364, P = 0.019) had a likelihood of reduction of dowry value. Finally, in terms of cost of treatment, abortion (OR = 0.449, P = 0.001), still births (OR = 0.208, P = 0.015), swollen testes (OR = 0.78, P = 0.014), weak calf/lambs (OR = 0.178, P = 0.007) and swollen joints (OR = 0.217, P = 0.003) significantly increased the costs of treatments. There was no impact on fat and meat and blood production.

Conclusion

Even though there was a huge socio-economic impact on milk production, infertility, sale value, and dowry, it was the costs of treatment that was significantly impacted on all symptoms associated with brucellosis on this community. A ‘One Health’ approach in tackling the brucellosis menace as a holistic approach is recommended for both humans and their livestock.

Identification, Genotyping and Antimicrobial Susceptibility Testing of Brucella spp. Isolated from Livestock in Egypt

Brucellosis is a highly contagious zoonosis worldwide with economic and public health impacts. The aim of the present study was to identify Brucella (B.) spp. isolated from animal populations located in different districts of Egypt and to determine their antimicrobial resistance. In total, 34-suspected Brucella isolates were recovered from lymph nodes, milk, and fetal abomasal contents of infected cattle, buffaloes, sheep, and goats from nine districts in Egypt. The isolates were identified by microbiological methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Differentiation and genotyping were confirmed using multiplex PCR for B. abortus, Brucella melitensis, Brucella ovis, and Brucella suis (AMOS) and Bruce-ladder PCR. Antimicrobial susceptibility testing against clinically used antimicrobial agents (chloramphenicol, ciprofloxacin, erythromycin, gentamicin, imipenem, rifampicin, streptomycin, and tetracycline) was performed using E-Test. The antimicrobial resistance-associated genes and mutations in Brucella isolates were confirmed using molecular tools. In total, 29 Brucella isolates (eight B. abortus biovar 1 and 21 B. melitensis biovar 3) were identified and typed. The resistance of B. melitensis to ciprofloxacin, erythromycin, imipenem, rifampicin, and streptomycin were 76.2%, 19.0%, 76.2%, 66.7%, and 4.8%, respectively. Whereas, 25.0%, 87.5%, 25.0%, and 37.5% of B. abortus were resistant to ciprofloxacin, erythromycin, imipenem, and rifampicin, respectively. Mutations in the rpoB gene associated with rifampicin resistance were identified in all phenotypically resistant isolates. Mutations in gyrA and gyrB genes associated with ciprofloxacin resistance were identified in four phenotypically resistant isolates of B. melitensis. This is the first study highlighting the antimicrobial resistance in Brucella isolated from different animal species in Egypt. Mutations detected in genes associated with antimicrobial resistance unravel the molecular mechanisms of resistance in Brucella isolates from Egypt. The mutations in the rpoB gene in phenotypically resistant B. abortus isolates in this study were reported for the first time in Egypt.

Serological and Molecular Identification of Brucella spp. in Pigs from Cairo and Giza Governorates, Egypt

Brucellosis is considered as endemic disease of animals and humans since thousands of years in Egypt. However, brucellosis in pigs has never been reported in Egypt. Thus, serological and molecular assays were applied to detect anti-Brucella antibodies and DNA in serum samples collected from pigs. In total 331 blood samples collected from male and female pigs at slaughterhouses of Cairo and Giza governorates were investigated using Brucella c- and i-ELISA and Brucella real-time PCR. Anti-Brucella antibodies were detected in 16 (4.83%) and 36 (10.8%) sera by i-ELISA and c-ELISA, respectively. Brucella DNA was detected in 10 (3.02%) seropositive samples and identified as Brucella melitensis (7/10) and Brucella suis (3/10). A higher prevelance was found in boars. This is the first study investigating pig brucellosis in Egypt. The results of this study will raise awareness for brucellosis in these farm animals and will help to develop effective control strategies.

Sero-diagnosis of brucellosis in sheep and humans in Assiut and El-Minya governorates, Egypt

Egypt is an endemic area with brucellosis, so wherever herd problem associated abortion is present, brucellosis should be suspected, and its sero-diagnosis is needed. The present study aimed to estimate the seroprevalence of brucellosis in sheep and their contact humans in Assiut and El-Minya Governorates where a history of abortion in sheep was the chief complaint of the farmers; besides; the appearance of signs of undulant fever among some contact humans. Also, to identify the risk factors for brucellosis seropositivity at human and animal level. Serum samples were collected from 189 sheep and 53 in contact humans in Assiut and El-Minya Governorates, Egypt, during 2017. Antibodies against brucellosis were measured in the serum samples using Rose Bengal Plate test (RBPT) and were further confirmed using Serum Tube Agglutination Test (STAT). The overall seroprevalence of brucellosis using RBPT was 15.87% in sheep and that in humans was 9.44% (5 of 53), respectively. STAT confirmed that 40% of the RBPT-positive reactor sheep were infected by Brucella abortus, 16.67% were containing Brucella melitensis and 20% were experiencing a mixed infection of both Br. abortus and Br. melitensis. Additionally, 80% of the RBPT-positive reactor humans were infected with Br. abortus only and 20% were having both species of Brucella. Among different analyzed variables in this study, the age and farming system of the examined sheep were statistically significant. There was no significant effect in relation to gender, abortion history and pregnancy status of the examined animals, however, higher exposure rates were found among males, abortive animals, and recently calved animals. Gender of the tested humans and presence of seropositive sheep in contact differed significantly in acquiring the infection. Nevertheless, other factors, including age, education, and profession were statistically insignificant on getting human brucellosis. These results indicate the high seroprevalence of brucellosis in humans and sheep in the study areas and generally in Egypt, and therefore, control programs should be implemented.

A Comprehensive Review of Common Bacterial, Parasitic and Viral Zoonoses at the Human-Animal Interface in Egypt

Egypt has a unique geographical location connecting the three old-world continents Africa, Asia and Europe. It is the country with the highest population density in the Middle East, Northern Africa and the Mediterranean basin. This review summarizes the prevalence, reservoirs, sources of human infection and control regimes of common bacterial, parasitic and viral zoonoses in animals and humans in Egypt. There is a gap of knowledge conerning the epidemiology of zoonotic diseases at the human-animal interface in different localities in Egypt. Some zoonotic agents are “exotic” for Egypt (e.g., MERS-CoV and Crimean-Congo hemorrhagic fever virus), others are endemic (e.g., Brucellosis, Schistosomiasis and Avian influenza). Transboundary transmission of emerging pathogens from and to Egypt occurred via different routes, mainly importation/exportation of apparently healthy animals or migratory birds. Control of the infectious agents and multidrug resistant bacteria in the veterinary sector is on the frontline for infection control in humans. The implementation of control programs significantly decreased the prevalence of some zoonoses, such as schistosomiasis and fascioliasis, in some localities within the country. Sustainable awareness, education and training targeting groups at high risk (veterinarians, farmers, abattoir workers, nurses, etc.) are important to lessen the burden of zoonotic diseases among Egyptians. There is an urgent need for collaborative surveillance and intervention plans for the control of these diseases in Egypt.