Tesfaye Sisay Tessema

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• DVM, MSc, PhD
• Professor of Health Biotechnology at Addis Ababa University

Bovine viral diarrhea (BVD) is caused by bovine viral diarrhea virus (BVDV), a member of the genus Pestivirus and in the family Flaviviridae. According to some studies, the disease incurs USD 1.5–2.5 billion per year and USD 0.50 to USD 687.80 per cow loss in beef and dairy farms, respectively. Using vaccines is among the strategies to prevent the...

Background Mastitis is one of the primary causes of economic and production losses in the dairy cattle industry. Bacterial infections are the most significant contributors to bovine mastitis, with Staphylococcus species among the most prevalent and challenging pathogens. This issue is especially severe in low- and middle-income countries, including...

Background Bovine rotavirus A (BRVA) and bovine coronavirus (BCoV) cause significant diarrhea in young calves, leading to health issues and economic losses in the cattle industry. This study aimed to detect and molecularly characterize BRVA and BCoV in calves from Addis Ababa, Ethiopia. Fecal samples were collected from 105 calves under six months...

Enteropathogenic Escherichia coli (EPEC) is a significant bacterial pathogen that causes infantile diarrhea, particularly in low- and middle-income countries. The lack of a reliable diagnostic method greatly contributes to the increased occurrence and severity of the disease. This study aimed at developing of a cost-effective, rapid, and efficient...

Background Campylobacter is a leading foodborne pathogen posing a significant One Health challenge due to its broad animal reservoirs and serious antibiotic resistance issues. Despite frequent human-animal-environment interactions in Ethiopia, One Health studies on the occurrence and transmission of Campylobacter are crucial but lacking. Methodolo...

Bovine viral diarrhea (BVD) is caused by bovine viral diarrhea virus (BVDV). The disease incurs $1.5-2.5 billion/year and $0.50 to $687.80/cow loss in beef and dairy farms respectively. This review aims to provide insights into the interaction of BVDV with host immunity, currently available vaccines, and strategies used to advance the vaccines. The...

Background Early detection and treatment of carbapenem-resistant Klebsiella pneumoniae (CRKP) could reduce the risk of developing life-threatening sepsis in childhood. However, little is known about sepsis caused by CRKP in children under-5 in developing countries. This study aimed to determine the epidemiology, antimicrobial resistance profile, as...

Brucellosis is a neglected zoonotic disease affecting livestock and humans that remains endemic in Ethiopia. Despite its prevalence, only a few studies have identified Brucella species circulating in livestock in the country. This study aimed to determine the Brucella species responsible for infections in livestock in the Afar region of Ethiopia an...

Brucellosis is a common zoonotic disease affecting livestock and humans globally. The disease is endemic in Ethiopian livestock. This study was conducted to estimate Brucella seropositivity and identify its risk factors in livestock, and practices that may expose pastoralists to the disease. Data were collected from 2133 animals across 149 househol...

Background Genomic structural variations (GSVs), notably copy number variations (CNVs), significantly shape genetic diversity and facilitate adaptation in cattle populations. Despite their importance, the genome-wide characterization of CNVs in indigenous Ethiopian cattle breeds—Abigar, Fellata, and Gojjam-Highland remains largely unexplored. In th...

Background Shigellosis is an acute gastroenteritis infection and one of Ethiopia’s most common causes of morbidity and mortality, especially in children under five. Antimicrobial resistance (AMR) has spread quickly among Shigella species due to inappropriate antibiotic use, inadequacies of diagnostic facilities, and unhygienic conditions. This stud...

Pathogenic E. coli strains could cause diarrheal infection both in animal and human hosts due to their virulence factors. Molecular detection of the virulent E. coli strains with antibiogram and determinants for the occurrence of diarrhea in children was conducted in Jimma. Cross-sectional study with purposive sampling was undertaken to isolate bac...

Mastitis is highly prevalent and causes significant economic loss in the Ethiopian dairy industry. An important aspect of monitoring dairy cow health and milk quality is understanding somatic cell count (SCC), composition and milk yield. This study aimed to evaluate milk SCC, composition, yield, and factors associated with the quality traits of Eth...

The emergence of antibiotic resistance in E. coli strains has sparked a fervent investigation of alternative therapies, such as the use of lytic bacteriophages. Phage genome sequence analysis is a novel method for learning more about proteins and other biomolecules encoded by phages, particularly phage-lytic enzymes that are crucial to the lysis of...

Background Early detection and proper management of maternal sepsis caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) can significantly reduce severe complications and maternal mortality. This study aimed to describe the epidemiology, antimicrobial resistance profile, and management of carbapenem-resistant K. pneumoniae among sepsis-suspe...

Background Calf diarrhea is a major cause of morbidity and mortality in the livestock sector worldwide and it can be caused by multiple infectious agents. In Ethiopia, cattle are the most economically important species within the livestock sector, but at the same time the young animals suffer from high rates of morbidity and mortality due to calf d...

Campylobacteriosis outbreaks have previously been linked to dairy foods. While the genetic diversity of Campylobacter is well understood in high-income countries, it is largely unknown in low-income countries, such as Ethiopia. This study therefore aimed to conduct the first genomic characterization of Campylobacter isolates from the Ethiopian dair...

The advancement of genetic engineering has revolutionized the field of immunology by allowing the utilization of intrinsic antibody structures. One of the biologics that are being produced by recombinant antibody technology is single-chain fragments variable (scFv). Genes of variable regions, the heavy and light chains that are genetically linked i...

Background Coagulase-negative Staphylococcus species are an emerging cause of intramammary infection, posing a significant economic and public health threat. The aim of this study was to assess the occurrence of coagulase-negative Staphylococcus species in bovine milk and dairy farms in Northwestern Ethiopia and to provide information about their a...

E. coli are genetically diverse bacteria which can live in different habitats. The E. coli genome has two components: The core genome which contains essential genes and is shared among all strains of the species; and the accessory genome which is highly variable among strains encompassing many mobile genetic elements. Despite the extensive dynamics...

Background: The prevalence and antibiogram of pathogenic E. coli strains which cause diarrhea vary from region to region, and even within countries in the same geographical area. In Ethiopia, diagnostic approaches to E. coli induced diarrhea in children less than five years of age are not standardized. The aim of this study was to determine the inv...

Indigenous animal genetic resources play a crucial role in preserving global genetic diversity and supporting the livelihoods of millions of people. In Ethiopia, the majority of the cattle population consists of indigenous breeds. Understanding the genetic architecture of these cattle breeds is essential for effective management and conservation ef...

In this study, our primary aim was to explore the genomic landscape of Barka cattle, a breed recognized for high milk production in a semi-arid environment, by focusing on genes with known roles in milk production traits. We employed genome-wide analysis and three selective sweep detection methods (ZFST, θπ ratio, and ZHp) to identify candidate gen...

Seasonal fluctuations influence foodborne illness transmission and affect patterns of microbial contamination of food. Previous investigations on the seasonality of Salmonella enterica prevalence in dairy products in Ethiopia have been minimal. However, such data are needed to inform strategic development of effective interventions to improve food...

Background Diarrheagenic Escherichia coli (E. coli) is a zoonotic pathogen that contaminates abattoir workers, slaughter environments, slaughter equipment, and carcasses during abattoir processing. Infection with E. coli is associated with the consumption of contaminated food and water, and it is a potential threat to the health and welfare of both...

12 Pathogenic Staphylococcus species, namely S. aureus, S. intermedius, and S. hyicus species, are 13 the primary causes of intra-mammary infections in cows and human food poisoning infections; 14 hence, this study aimed to assess the prevalence, antibiogram, virulence, and methicillin resistance 15 gene profiles of pathogenic Staphylococcus specie...

Diarrheagenic Escherichia coli (DEC) are the leading cause of infectious diarrhea and pose a significant global, regional, and national burden of disease. This study aimed to investigate the prevalence of six DEC pathotypes in children with diarrhea and determine their antibiotic resistance patterns. Samples from 107 diarrheagenic children were col...

Introduction There have been numerous studies that showed the presence of human papillomavirus (HPV) in breast cancer; nonetheless, there is ongoing debate regarding their association. Given few studies in Ethiopia, we aimed to investigate the magnitude of HPV infection in Ethiopian breast cancer patients. Methods A total of 120 formalin-fixed par...

Background Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbes have evolved to cause diarrhea, urinary tract infections, and septicemias. The emergence of antibiotic resistance urged the identification of an alternative strategy. The use of lytic bacteriophages against the c...

The emergence of antibiotic resistance in E. coli strains has sparked a fervent investigation of alternative therapies such as the use of lytic bacteriophages. Phage whole genome sequencing is a novel method for learning more about proteins and other biomolecules encoded by phages, particularly phage lytic enzymes that are crucial to the lysis of b...

Background Early detection and proper management of maternal sepsis caused by multidrug-resistant K. pneumoniae can significantly reduce severe complications and maternal mortality. This study aimed to describe the epidemiology, antimicrobial resistance profile, and management of carbapenem-resistant K. pneumoniae among sepsis-suspected maternal ca...

Listeriosis caused by Listeria monocytogenes often poses a significant threat to vulnerable populations. Dairy products have been implicated in outbreaks of listeriosis worldwide. In Ethiopia, studies have identified Listeria spp. and L. monocytogenes in various dairy products, but the genetic diversity and phylogenetic relationships of these bacte...

A longitudinal design with a simple random sampling method was used to collect and compare microbial hygiene levels between the dry season (January to April) and wet season (June to August). A total of 456 milk and cottage cheese samples were collected from each site along the dairy value chain from three regions. Enumeration of total aerobic mesop...

Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbes have evolved to cause diarrhea, urinary tract infections, and septicemias. The emergence of antibiotic resistance urged the identification of an alternative strategy. The use of lytic bacteriophages against the control of p...

Background Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbes have evolved to cause diarrhea, urinary tract infections, and septicemias. The emergence of antibiotic resistance urged the identification of an alternative strategy. The use of lytic bacteriophages against the c...

Purpose Different biological characteristics, therapeutic responses, and disease-specific outcomes are associated with different molecular subtypes of breast cancer (BC). Although there have been different studies on BC in the Ethiopian capital city of Addis Ababa, there have been few studies in other parts of the nation, and none have evaluated bi...

Over time, indigenous cattle breeds have developed disease resistance, heat tolerance, and adaptability to harsh environments. Deciphering the genetic mechanisms underlying adaptive traits is crucial for their improvement and sustainable utilization. For the first time, we performed whole-genome sequencing to unveil the genomic diversity, populatio...

Simple Summary Abigar cattle, native to southwestern Ethiopia’s hot and humid environment, are recognized for their adaptability and vital contribution to local livelihoods and the livestock value chain. Investigating their genetic basis for adaptive traits is crucial for sustainable use. However, there is a paucity of studies on genomic diversity,...

Simple Summary: Abigar cattle, native to southwestern Ethiopia's hot and humid environment, are recognized for their adaptability and vital contribution to local livelihoods and the livestock value chain. Investigating their genetic basis for adaptive traits is crucial for sustainable use. However, there is a paucity of studies on genomic diversity...

Introduction Matrix metalloproteinases (MMPs) play a pathophysiological role in cancer initiation and progression. Numerous studies have examined an association between MMP-2, MMP-9, and MMP-11 expression and clinicopathological characteristics of breast cancer (BC); however, no research has been done on the MMP expression levels in BC cases from E...

Seasonal fluctuations influence foodborne illness transmission and affect patterns of microbial contamination of food. Previous investigations on the seasonality of Salmonella enterica prevalence in dairy products in Ethiopia have been minimal. However, such data are needed to inform strategic development of effective interventions to improve food...

Purpose: This study aimed at evaluating the performance of the Loop Mediated Isothermal Amplification (LAMP) diagnostic test, which targets the putative Fimbria protein-encoding gene (Z3276) for rapid and specific detection of locally isolated enterohemorrhagic Escherichia coli (EHEC) O157:H7. Results: A total number of 40 locally available bact...

Background: Shigella and parasitic infections are common public health problems throughout the world. Shigellosis is an acute gastroenteritis infection and one of Ethiopia's most common causes of morbidity and mortality, especially in children under five. High resistance rates to commonly used antibiotic agents have been documented in different lo...

Campylobacter is one of the major causes of gastroenteritis and is commonly transmitted through the consumption of raw milk or improperly pasteurized milk. A cross-sectional study was conducted from January 2019 to March 2020 in four study sites in the Oromia region of Ethiopia to isolate, identify, and estimate the prevalence of Campylobacter spec...

Background Bloodstream infection due to beta-lactamase and carbapenemase-producing gram-negative bacteria poses a substantial challenge to the effectiveness of antimicrobial treatments. Therefore, this study aimed to investigate the magnitude of beta-lactamase, carbapenemase-producing gram-negative bacteria, and associated risk factors of bloodstre...

Background Coagulase-negative Staphylococcus species are an emerging cause of intramammary infection, posing a significant economic and public health threat. The cross-sectional study was conducted to isolate and assess virulence factors and antibiogram profiles of coagulase-negative Staphylococcus species in 290 milk samples collected from Februar...

Background: Breast cancer (BC) is the most common type of cancer in Ethiopia. The incidence of BC is also rising, but the exact figure is still poorly known. Therefore, this study was conducted to address the gap in epidemiological data on BC in southern and southwestern Ethiopia. Materials and Methods: This is a five-year (2015–2019) retrospective...

Background Ethiopia rolled out primaquine nationwide in 2018 for radical cure along with chloroquine for the treatment of uncomplicated Plasmodium vivax malaria in its bid for malaria elimination by 2030. The emergence of anti-malarial drug resistance would challenge the elimination goal. There is limited evidence on the emergence of chloroquine dr...

Animal sourced foods, such as dairy products, are common sources of Salmonella enterica, a foodborne pathogen of increasing global concern, particularly in developing countries. In Ethiopia, most data on the prevalence of Salmonella in dairy products is highly varied and limited to a specific region or district. Furthermore, there is no data availa...

E. coli are frequently isolated food-borne pathogens from meat, milk, and their products. Moreover, there has been a significant rise in the antimicrobial resistance patterns of E. coli O157:H7 to commonly used antibiotics. A cross-sectional study was conducted from October 2019 to July 2021 to estimate prevalence and identify associated factors of...

Cattle are central to the lives and diverse cultures of African people. It has played a crucial role in providing valuable protein for billions of households and sources of income and employment for producers and other actors in the livestock value chains. The long-term natural selection of African cattle typically signals signatures in the genome,...

Background: In Ethiopia, livestock contributes 45% of agricultural GDP. Despite the economic role played by the sector, there have been little efforts to genetically improve the indigenous cattle. Morphological characterization of selected Ethiopian indigenous cattle has been made for (Bonga, Jimma, and Kerayu) cattle types. But, the selected indi...

Background: Understanding the genetic foundation of locally adapted indigenous cattle breeds is critical information for developing appropriate genetic improvement and conservation initiatives. To investigate breed-specific SNPs, and minor allele frequency of three Ethiopian cattle breeds Begait, (n = 40), Boran (n = 40), and Fogera (n = 43) were g...

Different E. coli pathotypes are common zoonotic agents. Some of these pathotypes cause recurrent and widespread calf diarrhea and contribute to significant economic losses in the livestock sector worldwide in addition to putting humans at risk. Here, we investigated the occurrence of E. coli pathotypes in diarrheic calves in Ethiopia kept under va...

Background The prevalence and antibiogram of pathogenic E. coli strains which cause diarrhea vary from region to region, and even within countries in the same geographical area. In Ethiopia, diagnostic approaches to E. coli induced diarrhea in children less than five years of age are not standardized. The aim of this study was to determine the invo...

Animal sourced foods, such as dairy products, are common sources of Salmonella enterica , a foodborne pathogen of increasing global concern, particularly in developing countries. In Ethiopia, most data on the prevalence of Salmonella in dairy products is highly varied and limited to a specific region or district. Furthermore, there is no data avail...

Background: Despite the availability of genomic methods for determining the origin and divergence of domestic cattle in East Africa, particularly Ethiopia, knowledge regarding their genetic adaptability and divergence remain limited. To investigate signatures of selection Ethiopian cattle populations were genotyped with an 80K SNP array and Europea...

Diarrheagenic Escherichia coli strains are an essential cause of diarrheal infection in younger children and animals. The study was focused on understanding the associated characteristics of various DEC strains among children and calves, establishing the possible zoonotic transmission, and determining their antibiotic resistance patterns. Samples f...

Diarrheagenic Escherichia coli strains are an essential cause of diarrheal infection in younger children and animals. The study was focused on understanding the associated characteristics of various DEC strains among children and calves, establishing the possible zoonotic transmission, and determining their antibiotic resistance patterns. Samples f...

Microbial hygiene of raw and pasteurised milk and cottage cheese samples was assessed along the value chain in three regions of Ethiopia between December and May 2020. A total of 912 samples (368 raw milk, 368 pasteurised milk and 176 cottage cheese samples) were collected from producers, collectors, processors, and retailers. Raw milk and pasteuri...

A cross-sectional study was conducted to investigate the prevalence and risk factors for contamination of Ethiopian dairy products with Campylobacter. A total of 912 dairy food samples were collected from establishments of 682 study participants that were interviewed. Samples were tested for Campylobacter by following the ISO 10272–1:2017 standard...

A longitudinal study was undertaken to investigate E. coli using standard biochemical and sugar fermentation tests. Faecal samples were taken from calves purposively from three selected dairy farms in Bishoftu Ethiopia. Four different sampling times were used to observe the detection rate of E. coli. The overall detection of E. coli was 84/104 (80....

Shiga toxin-producing Escherichia coli (STEC) are the leading causes of diarrhea and death of humans worldwide. Many diagnostic assays have been developed to aid for the diagnosis of STEC strain; however, they have limitations. Thus, this study was aimed at designing rapid, effective, sensitive and specific immunodiagnostic assay for STEC strain de...

Backgrounds: O157:H7 E. coli has been implicated in the worldwide outbreak of food and water borne diseases. Early and effective diagnosis are the pivotal concerns for clinics and hospitals for prompt reporting of outbreaks, prevent more cases and treat the infection in appropriate time. Most of common diagnostic methods are constrained by signific...

E. coli are frequently isolated food-borne pathogens from meat, milk, and their products. Moreover, there has been a significant rise in the antimicrobial resistance patterns of E. coli O157:H7 to commonly used antibiotics. A cross-sectional study was conducted from October, 2019 to July, 2021 to estimate prevalence and identify associated factors...

Introduction: Pathogenic Escherichia coli strains cause diarrheal infection in children due to their virulence factors. A nonanalytical observational study followed by a purposive sampling technique was conducted from October 2017 to June 2018, to determine the antimicrobial susceptibility patterns and molecularly detect pathogenic Escherichia col...

Introduction Understanding the genetic foundation of locally adapted indigenous cattle breeds is critical information for developing appropriate genetic improvement and conservation methods and initiatives. Methods To investigate breed-specific SNPs, and minor allele frequency in three Ethiopian cattle breeds Begait, (n = 40), Boran (n = 40), and...

Availing information on genetic parameters of traits of interest for a given population is a prerequisite for effective genetic improvement programs. The objective of this research was to estimate the covariance components and genetic parameters of birth weight (BW), weaning weight (WW), and growth rate (ADG) traits of Boran cattle maintained at Di...

Background: Escherichia coli is a known normal flora of the gastrointestinal tract frequently used as model for various research trials. Potential gain and loss of virulent genes enable it to become pathogenic and causes calf diarrhea while beneficial ones subsidize vitamin K2. These virulent genes are found on plasmids, genomes or integrated on ba...

Despite the availability of genomic methods for determining the origin and divergence of domestic cattle in East Africa, particularly Ethiopia, knowledge regarding their genetic adaptability and divergence remain limited. To investigate signatures of selection and linkage disequilibrium Ethiopian cattle populations were genotyped with an 80K SNP ar...

Despite the availability of genomic methods for determining the origin and divergence of domestic cattle in East Africa, particularly Ethiopia, knowledge regarding their genetic adaptability and divergence remain limited. To investigate signatures of selection and linkage disequilibrium Ethiopian cattle populations were genotyped with an 80K SNP ar...

Brucellosis is a zoonotic disease of considerable economic and public health significance globally. Despite the limited bacteriological evidence, a large number of serological works revealed that it is prevalent both in livestock and humans in Ethiopia. The current comprehensive review was carried out to provide apparent pooled seroprevalence (APS)...

Background Bloodstream infections (BSIs) are significant causes of morbidity and mortality in Ethiopia and worldwide. Alarming is the rapid global spread of antimicrobial resistance (AMR) in bacteria. Objective To determine the microbial profile, antimicrobial susceptibility pattern, and associated risk factors for bloodstream infections in Tikur...