Many emerging and reemerging human pathogens are derived from animals or from animal tissues, waste, or products. A wide range of species including insects (eg, mosquitos), wild animals (eg, rodents, bats, and monkeys), draft animals (eg, horses and mules), and livestock animals (eg, swine, poultry, and cattle) have been implicated in transmission of various highly pathogenic infections, including parasitic, bacterial, and viral diseases, to humans. Among the most deadly emerging zoonotic diseases are viral hemorrhagic fevers, including those caused by the filoviruses, EBOV and MARV. The zoonotic potential of these viruses was identified at the time of their discovery during
Rift Valley fever virus is a mosquito-borne pathogen of livestock and humans that historically has been responsible for widespread and devastating outbreaks of severe disease throughout Africa and, more recently, the Arabian Peninsula. The virus was first isolated and RVF disease was initially characterized following the sudden deaths (over a 4-week period) of approximately 4,700 lambs and ewes on a single farm along the shores of Lake Naivasha in the Great Rift Valley of Kenya in 1931.1 Since that time, RVF virus has caused numerous economically devastating epizootics that were characterized by sweeping abortion storms and mortality ratios
Leptospirosis, a bacterial zoonotic disease with a worldwide distribution, is caused by spirochetes of the genus Leptospira. Leptospirosis encompasses a wide spectrum of clinical disease in humans, including multiorgan failure with a high mortality rate. Because of the lack of specific symptoms associated with this disease, it is difficult to make an accurate diagnosis in a timely manner. In 1886, Adolph Weil1 was one of the first to describe the severe or icteric form of leptospirosis in Heidelberg, Germany. Descriptions of the disease among agricultural workers and miners in Japan and China were reported earlier.2
Animal bites continue to pose major public health challenges. Since publication of the previous report1 on this topic for this series in 1988, much has been researched and reported regarding animal bites among populations of humans. The intent of this article was not to exhaustively review all literature published since 1988, but to focus on aspects of animal bites (dog and cat bites in particular) that were novel or noteworthy with respect to previously unrecognized injuries or cause of death2–7 or bite-wound pathogens,8–10 the role of individual organisms in polymicrobial infections,11 risk
Bovine spongiform encephalopathy was described as a new disease of cattle in 1987.1 From its first recorded appearance in England, more than 184,500 cases have been confirmed throughout the United Kingdom, an epizootic that peaked in 1992.2 However, because the incubation period of this disease exceeds the usual slaughter age for cattle, these recorded case numbers represent only a fraction of the infected animals; it has been calculated that since 1980, approximately 2 million cattle have developed BSE in the United Kingdom.3 The disease has now been confirmed in native-born cattle in 25 countries
Transmissible spongiform encephalopathies affect humans and other animals. Clinically, the diseases involve severe, progressive neurodegeneration with an invariably fatal outcome. The TSEs are linked by the unusual nature of their causative agent, which is believed to be a transmissible protein devoid of nucleic acid. This protein, known as a prion (a pseudoabbreviation for proteinaceous infectious particle), is a hallmark feature and purported pathogen of human and other animal TSEs.1 For many years, the natural transmission of TSEs appeared to be almost exclusively relegated to their respective phylogenic and species lineages; however, the association in the mid-1990s between a
Brucellosis is one of the most common zoonotic diseases in the world and, as such, poses a major threat to human health and animal agriculture. In the United States, however, concentrated animal disease control programs, occupational safety practices, and food safety efforts have diminished the relative impact of brucellosis over the last half century. At its most basic level, brucellosis in humans is dependent on the presence of Brucella spp among other animals with which people have direct or indirect contact. As with many classic zoonotic diseases, the role of veterinarians is critical for the detection and continued
Glanders is a highly contagious bacterial disease of horses, mules, and donkeys that is characterized by respiratory, cutaneous, and lymphatic nodular lesions. The disease is zoonotic, affecting persons in close contact with infected animals or those working with the organism in laboratory settings. Once prevalent worldwide, glanders has been eradicated from most countries; however, focal outbreaks do still occur. Burkholderia mallei, the causative organism of glanders, is considered a potential bioterrorism agent and has been used historically for this purpose. Control and prevention measures for glanders involve evaluation of susceptible equids, quarantine measures, depopulation of infected animals, and
Anthrax is an ancient zoonotic disease that continues to threaten human and animal health. It remains enzootic in many regions of the world, and cases of anthrax among humans are frequently reported. Outbreaks occur annually among wild and domestic herbivores in North America, although this infection is no longer a substantial cause of human disease in the United States. As a result of the occurrence of anthrax worldwide, and because of its bioterrorist potential, veterinarians should understand the epidemiology, clinical signs, treatment, and control of anthrax.
Anthrax is the infection caused by the spore-forming bacterium Bacillus anthracis.
West Nile virus was first identified in Africa in 1937, and subsequently, Africa, Europe, Australia, and Asia were recognized as regions in which the virus was endemic.1 In 1999, concurrent outbreaks of encephalitis among crows, humans, and horses in New York State triggered an investigation by human and veterinary health officials that led to the initial detection of WNV in the western hemisphere.2,3 West Nile virus is now the leading cause of human arboviral encephalitis in the United States.4 It is found throughout the western hemisphere, including North America, Central America, South America, and