MERS-CoV‒Specific T-Cell Responses in Camels after Single MVA-MERS-S Vaccination.

We developed an ELISPOT assay for evaluating Middle East respiratory syndrome coronavirus (MERS-CoV)‒specific T-cell responses in dromedary camels. After single modified vaccinia virus Ankara-MERS-S vaccination, seropositive camels showed increased levels of MERS-CoV‒specific T cells and antibodies, indicating suitability of camel vaccinations in disease-endemic areas as a promising approach to control infection.

Fifty Years of Research on Camelids and the Contribution of Genetics and Genomics: A Scientometrics Evaluation

The population and importance of camels in human life have improved in recent years. As genetics and genomics are becoming a more comprehensive section of life sciences, studying genetic/genomic aspects of the camelid nutrition, milk production, reproduction, immunity, disease and racing ability has become common in recent years. This study was conducted based on text mining and scientometrics techniques. To employ relevant information from Web of Science (WoS), a search strategy was developed to retrieve the "genetics or genomics” and words/phrases related to "camelids”. The statistical population of this study included 3830 publications over a period of 50 years (1971–2020). A total of 3830 publications were retrieved that included 3269 research articles (85.35% of the publications) and 224 review articles (5.85% of the publications). The most frequent subject groups were "Veterinary Sciences” including 862 publications. In total, articles on camelid genomics were published in 1345 journals. Moreover, 127 countries contributed to these 3830 publications, with the USA being the leading country both in number of publications and international collaboration. During the 1971–2010 time period, the phrases "MERS-CoV” and "coronavirus” did not exist in the literature at all, while in the last decade, with 140 and 63 times (5.36% and 2.41%, respectively), they were the most frequent keywords. In general, the most important topics studied from the perspective of camelid genomics have been population genetics and pathogens and their diagnosis, as well as camelid immunity. Future studies should pay special attention to the specificity of camelid genomics for hosting the coronavirus. Furthermore, the special structure of humoral immunity in camels makes this section attractive in immunogenetics research. © 2023, University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering. All rights reserved.

Evaluation of a Rapid Immunochromatographic Middle East Respiratory Syndrome Coronavirus Antigen Detection Assay

Middle East respiratory syndrome coronavirus (MERS-CoV) infection in humans has a high mortality of >30%. Dromedaries are the reservoir of MERS-CoV and the main source of human infections. However, MERS-CoV infections in dromedaries are usually subclinical. Rapid diagnosis of MERS-CoV infection in these animals is important in preventing camel-to-human transmission of the virus. The possible cross-reactivity of a previously reported rapid nucleocapsid protein-based antigen detection assay for MERS-CoV was examined with different CoVs, including Tylonycteris bat CoV HKU4, dromedary camel CoV UAE-HKU23, human CoV-229E, human CoV-OC43, severe acute respiratory syndrome CoV-2 and rabbit CoV HKU14, where none of them showed false-positive results. The assay was further validated using quantitative real-time reverse transcription-polymerase chain reaction-confirmed MERS-CoV-positive and MERS-CoV-negative dromedary nasal samples collected in Dubai, the United Arab Emirates, which showed that the rapid antigen detection assay has a specificity of 100% and sensitivity of 91.7%.

Chapter 3 - Middle Eastern respiratory syndrome

Middle East respiratory virus syndrome (MERS) is a viral disease that primarily affects the respiratory system, but also has a major impact on the kidneys and nervous system and, to a lesser extent, on the intestines, liver, and heart. Over 2500 cases and 850 deaths have been confirmed as of 2019. The fatality rate is approximately 35%, more than that caused by severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 (that causes COVID-19). The first known case of MERS in humans was reported in 2012 in Saudi Arabia but the virus was present in stored serum samples from dromedary (one-humped) camels from Africa and the Middle East for decades before that time. Since then, it spread to at least 27 countries around the world, most of which are related to travel to the Arabian Peninsula. The coronavirus that causes MERS, MERS-CoV, is related to several other human coronaviruses that typically cause cold-like illness as well as to SARS-CoV and SARS-CoV-2. MERS-CoV is from the subgenus Merbecovirus, while SARS-CoV and SARS-CoV-2 are in Sarbecovirus. MERS-CoV also uses dipeptidyl peptidase 4 as its host cell receptor, while SARS-CoV and SARS-CoV-2 use angiotensin-converting enzyme 2. While MERS-CoV is transmittable between people in close contact with an infected person, many infections are zoonotic and are due to inhaling infectious respiratory droplets from dromedaries or consuming their raw milk or urine. Many cases are nosocomial (acquired in healthcare facilities). Fortunately, MERS-CoV only can pass through several rounds of human-to-human transmission, unlike SARS-CoV-2. Much of the pathology is due to an excessive inflammatory type of immune response caused by cytokines and chemokines, abnormal blood coagulation, and virus-induced apoptosis (programmed cell death). Bats appear to be the reservoir hosts and should be monitored for possible zoonotic transmission outside of the Middle East, in line with the One Health approach.

Chapter 6 - Coronaviruses of agricultural and companion animals with the potential for zoonotic transmission

Several human coronaviruses cause high mortality rates and are highly contagious, while others cause cold-like illnesses. These viruses are believed to enter human populations by zoonotic transmission from animal intermediate hosts from live animal markets in China [severe acute respiratory syndrome coronaviruses (SARS-CoV) from palm civets/raccoon dogs and SARS-CoV-2 possibly from pangolins] or dromedary camels in the Arabian Peninsula (Middle East respiratory syndrome coronavirus). Some bats may act as reservoir hosts. While much focus on the possible reservoir and intermediate hosts for future zoonotic transmission focuses on bats or rodents, humans spend much more time with agricultural animals, including cattle, pigs, camelids, and horses, particularly pigs, which host six coronaviruses. One pig coronavirus is a deltacoronavirus, a genus that almost exclusively contains bird viruses. The species Betacoronavirus-1, represented by a bovine coronavirus, contains members that infect other animal hosts, as do the Alphacoronavirus-1 species. Humans spend large amounts of time in the company of their companion animals, such as cats and dogs. Some contact is intimate, including allowing these animals to sleep with their owners and lick their faces. In addition to possible zoonotic transmission, humans transmit coronaviruses, including SARS-CoV-2, to domestic and captive exotic cats, some of which are endangered. Human-to-cat transmission of SARS-CoV-2 has caused severe disease in juvenile domestic cats. People are also regularly in contact with animal fecal material. Some diseases caused by animal coronaviruses are typically mild, while others cause severe, life-threatening diseases. Both morbidity and mortality in agricultural animals have a great economic impact on developing and developed regions of the world. Due to close, prolonged contact between humans and agricultural and companion animals, it may be a matter of great importance to spend more time and resources studying the potential for coronaviruses of domestic animals to cause zoonotic transmission.

Serosurvey for Middle East respiratory syndrome coronavirus antibody in dromedary camels and human patients at a secondary care hospital, Illela, Northwest Nigeria.

Middle East respiratory syndrome (MERS) is a serious emerging zoonosis. It is characterized by severe infection of the respiratory tract in humans. Dromedary camels are considered to be the most probable origin of the pathogenic Middle East respiratory syndrome coronavirus (MERS-CoV). This cross-sectional survey was carried out to ascertain the seroprevalence of MERS-CoV in dromedary camels at Illela border and human patients in a secondary care hospital in Illela, Sokoto State, Nigeria from November 2016 to January 2017. Serum samples from 74 camels and 39 human patients were collected while a data form was administered to the camel handlers (40) and human patients to obtain information on zoographic characteristics of dromedary camels, demographic characteristics of camel handlers and human patients and some practices of both groups which are likely to predispose to MERS-CoV infection. The serum samples were analyzed for antibodies against MERS-CoV using the indirect Enzyme-Linked Immuno-Sorbent Assay (ELISA). All the camels sampled were seropositive against MERS-CoV and 74% of the human patients had antibodies against MERS. All handlers treated their camels without consulting veterinarians and there was little or no biosecurity measures undertaken. Age, sex, and occupation were not significant determinants for the presence of MERS-CoV antibody in human patients sampled. This study serves as a baseline for similar researches and due to the high seroprevalence obtained in this study for both camels and humans, there is need for trained personnel, surveillance and diagnostic tools at our border posts and animal markets. Supplementary information: The online version contains supplementary material available at 10.1007/s00580-022-03351-3.

Exploring the potential roles of some rodents in the transmission of the Middle East respiratory syndrome coronavirus.

Middle East respiratory syndrome coronavirus (MERS-CoV) is one of the recently identified zoonotic coronaviruses. The one-hump camels are believed to play important roles in the evolution and transmission of the virus. The animal-to-animal, as well as the animal-to-human transmission in the context of MERS-CoV infection, were reported. The camels shed the virus in some of their secretions, especially the nasal tract. However, there are many aspects of the transmission cycle of the virus from animals to humans that are still not fully understood. Rodents played important roles in the transmission of many pathogens, including viruses and bacteria. They have been implicated in the evolution of many human coronaviruses, especially HCoV-OC43 and HCoV-HKU1. However, the role of rodents in the transmission of MERS-CoV still requires more exploration. To achieve this goal, we identified MERS-CoV that naturally infected dromedary camel by molecular surveillance. We captured 15 of the common rodents (rats, mice, and jerboa) sharing the habitat with these animals. We collected both oral and rectal swabs from these animals and then tested them by the commercial MERS-CoV real-time-PCR kits using two targets. Despite the detection of the viral shedding in the nasal swabs of some of the dromedary camels, none of the rodents tested positive for the virus during the tenure of this study. We concluded that these species of rodents did not harbor the virus and are most unlikely to contribute to the transmission of the MERS-CoV. However, further large-scale studies are required to confirm the potential roles of rodents in the context of the MERS-CoV transmission cycle, if any.

Prevalence of Middle East Respiratory Syndrome Coronavirus in Dromedary Camels, Tunisia.

Free-roaming camels, especially those crossing national borders, pose a high risk for spreading Middle East respiratory syndrome coronavirus (MERS-CoV). To prevent outbreaks, active surveillance is necessary. We found that a high percentage of dromedaries in Tunisia are MERS-CoV seropositive (80.4%) or actively infected (19.8%), indicating extensive MERS-CoV circulation in Northern Africa.

The Recombination Potential between SARS-CoV-2 and MERS-CoV from Cross-Species Spill-over Infections.

Countries in the Middle-East (ME) are tackling two corona virus outbreaks simultaneously, Middle-Eastern Respiratory Syndrome Coronavirus (MERS-CoV) and the current Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Both viruses infect the same host (humans) and the same cell (type-II alveolar cells) causing lower respiratory illnesses such as pneumonia. Molecularly, MERS-CoV and SARS-CoV-2 enter alveolar cells via spike proteins recognizing dipeptidyl peptidase-4 and angiotensin converting enzyme-II, respectively. Intracellularly, both viruses hide in organelles to generate negative RNA strands and initiate replication using very similar mechanisms. At the transcription level, both viruses utilise identical Transcription Regulatory Sequences (TRSs), which are known recombination cross-over points during replication, to transcribe genes. Using whole genome alignments of both viruses, we identify clusters of high sequence homology at ORF1a and ORF1b. Given the high recombination rates detected in SARS-CoV-2, we speculate that in co-infections recombination is feasible via TRS and/or clusters of homologies. Accordingly, here we recommend mitigation measure and testing for both MERS-CoV and SARS-CoV-2 in ME countries.

Influenza A Virus Infections in Dromedary Camels, Nigeria and Ethiopia, 2015-2017.

We examined nasal swabs and serum samples acquired from dromedary camels in Nigeria and Ethiopia during 2015-2017 for evidence of influenza virus infection. We detected antibodies against influenza A(H1N1) and A(H3N2) viruses and isolated an influenza A(H1N1)pdm09-like virus from a camel in Nigeria. Influenza surveillance in dromedary camels is needed.

Risk factors for serological evidence of MERS-CoV in camels, Kenya, 2016-2017.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging viral disease and dromedary camels are known to be the source of human spill over events. A cross-sectional epidemiological surveillance study was carried out in Kenya in 2017 to, 1) estimate MERS-CoV antibody seropositivity in the camel-dense counties of Turkana, Marsabit, Isiolo, Laikipia and Nakuru to identify, and 2) determine the risk factors associated with seropositivity in camels. Blood samples were collected from a total of 1421 camels selected using a multi-stage sampling method. Data were also collected from camel owners or herders using a pre-tested structured questionnaire. The sera from camel samples were tested for the presence of circulating antibodies to MERS-CoV using the anti-MERS-CoV IgG ELISA test. Univariate and multivariable statistical analysis were used to investigate factors potentially associated with MERS-CoV seropositivity in camels. The overall seropositivity in camel sera was 62.9 %, with the highest seropositivity recorded in Isiolo County (77.7 %), and the lowest seropositivity recorded in Nakuru County (14.0 %). When risk factors for seropositivity were assessed, the "Type of camel production system" {(aOR = 5.40(95 %CI: 1.67-17.49)}, "Age between 1-2 years, 2-3 years and above 3 years" {(aOR = 1.64 (95 %CI: 1.04-2.59}", {(aOR = 3.27 (95 %CI: 3.66-5.61)}" and {(aOR = 6.12 (95 %CI: 4.04-9.30)} respectively and "Sex of camels" {(aOR = 1.75 (95 %CI: 1.27-2.41)} were identified as significant predictors of MERS-CoV seropositivity. Our studies indicate a high level of seropositivity to MERS-CoV in camels in the counties surveyed, and highlights the important risk factors associated with MERS-CoV seropositivity in camels. Given that MERS-CoV is a zoonosis, and Kenya possesses the fourth largest camel population in Africa, these findings are important to inform the development of efficient and risk-based prevention and mitigation strategies against MERS-CoV transmission to humans.

The Middle East respiratory syndrome coronavirus in the breath of some infected dromedary camels (Camelus dromedarius).

Dromedary camels remain the currently identified reservoir for the Middle East respiratory syndrome coronavirus (MERS-CoV). The virus is released in the secretions of the infected camels, especially the nasal tract. The virus shedding curve through the nasal secretions was studied. Although human transmission of the virus through the respiratory tract of close contact people with dromedary reported previously, the exact mechanism of transmission is still largely unknown. The main goal of this study was to check the possibility of MERS-CoV shedding in the exhaled air of the infected camels. To achieve this goal, we conducted a follow-up study in one of the dromedary camel herds, December 2018-April 2019. We tested nasal swabs, breath samples from animals within this herd by the real-time PCR. Our results showed that some of the tested nasal swabs and breath were positive from 24 March 2019 until 7 April 2019. The phylogenetic analysis of the obtained S and N gene sequences revealed the detected viruses are clustering together with some human and camel samples from the eastern region, especially from Al-Hufuf city, as well as some samples from Qatar and Jordon. These results are clearly showing the possibility of shedding of the virus in the breath of the infected camels. This could explain, at least in part, the mechanism of transmission of MERS-CoV from animals to humans. This study is confirming the shedding of MERS-CoV in the exhaled air of the infected camels. Further studies are needed for a better understanding of the MERS-CoV.

Seroprevalence of Middle East Respiratory Syndrome Corona Virus in dromedaries and their traders in upper Egypt.

INTRODUCTION: Camel trade in Egypt depends mainly on importation. Seemingly healthy imported camels are responsible for the ingress of serious diseases into Egypt. A striking example of this concerning public health globally is the Middle East respiratory coronavirus (MERS-CoV) which causes case fatalities of over 34%. Here, we determined the seroepidemiological situation of the MERS-CoV in imported camels and their traders in Upper Egypt. METHODOLOGY: Sera of sixty-three dromedaries and twenty-eight camel traders were recruited (January 2015-December 2016). The age, gender, and sampling locality of each sampled camel and human were obtained. Semi-quantitative anti-MERS-CoV IgG ELISAs which utilize the purified spike protein domain S1 antigen of MERS coronavirus (MERS-CoV S1) were used to detect specific IgG antibodies against the virus. RESULTS: The data showed that 58.73% of imported camels and 25% of traders had antibodies specific to MERS-CoV. Interestingly, like seroreactive camels, all seropositive humans were apparently healthy without any history of developing severe respiratory disease in the 14 days prior to sampling. Having specific antibodies among the examined camel sera was significantly different (P < 0.0001) in relation to various sampling localities, gender and age groups. In contrast, the seropositivity rate of MERS-CoV IgG in humans did not differ significantly by any of the studied factors. CONCLUSIONS: The current study provides the first serological evidence of occupational exposure of humans to MERS-CoV in Africa. Additionally, it reports that imported camels could be implicated in introducing MERS-CoV into Egypt. Accordingly, application of strict control measures to camel importation is a priority.