Coccidiosis in dogs-100 years of progress.

Until 1970, coccidian parasites of dogs were considered to have a direct fecal-oral life cycle like Eimeria in poultry. They were thought to be non-host specific and infect both dogs and cats. Studies conducted in the 1970s revealed that dog coccidia were host-specific and had transport or paratenic hosts that were infected with an encysted stage containing a single organism, the monozoic tissue cyst. There are still considerable confusion and uncertainties concerning the life cycles and pathogenicity of coccidian parasites of dogs. The present paper reviews the history, taxonomy, life cycles, pathogenicity, epidemiology, diagnosis, and treatment of conventional coccidian parasites previously called Isospora spp., currently designated Cystoisospora spp. that infect canines.

Canine caliciviruses of four serotypes from military and research dogs recovered in 1963-1978 belong to two phylogenetic clades in the Vesivirus genus.

BACKGROUND: Vesiviruses (family Caliciviridae) had been shown capable of invading a variety of host species, raising concern of their zoonotic potential. Since the 1980's, several canine caliciviruses (CaCV) isolates have been reported and are phylogenetically related to the vesiviruses with features distinct from both Vesicular exanthema of swine virus (VESV) and Feline calicivirus (FCV) species in phylogeny, serology and cell culture specificities. Etiological studies of canine diseases in dogs used for military services and laboratory studies were conducted in 1963-1978 at the Walter Reed Army Institute of Research. Multiple known and unknown viral pathogens including caliciviruses were recovered. METHODS: Four unidentified isolates were recovered in Walter Reed Canine Cells (WRCC) from respiratory, fecal and penile specimens. Physicochemical tests, electron microscopy, viral cultivation in human and animal cells, antibody neutralization assays, and recently the genome sequencing were used to characterize the isolates. Sera from these dogs and their cohorts were tested with the isolates to determine origin and prevalence of the infections. RESULTS: The viral isolates were small non-enveloped spherical RNA virions, 27 to 42 nm in diameter with cup-like structures, indicating they are caliciviruses. They propagated in WRCC and MDCK cells, not in either other canine cells or human and other animal cells. Each isolate is antigenically distinct and react with dog sera in respective cohorts. The genomes have nucleotide identities ranging from 70.3% to 90.7% and encode the non-structural polyprotein (1810 amino acids), major capsid protein (691 amino acids) and minor structural protein (134 amino acids). They belong to two different phylogenetic clades in Vesivirus genus with close relation with canine calicivirus (CaCV). CONCLUSIONS: These CaCV isolates have restricted cell tropism, antigenic diversity and genetic variation. Further investigation will shed light on antigenic relation to other vesiviruses, and its pathogenicity for dogs and potential infectivity to other animals. Together with the previously reported CaCV strains provides significant evidence to support the formation of a new CaCV species in the Vesivirus genus.

The history of rabies in the Western Hemisphere.

Before the introduction of control programs in the 20th century, rabies in domestic dogs occurred throughout the Western Hemisphere. However, historical records and phylogenetic analysis of multiple virus isolates indicate that, before the arrival of the first European colonizers, rabies virus was likely present only in bats and skunks. Canine rabies was either rare or absent among domestic dogs of Native Americans, and first arrived when many new dog breeds were imported during the period of European colonization. The introduction of the cosmopolitan dog rabies lyssavirus variant and the marked expansion of the dog population provided ideal conditions for the flourishing of enzootic canine rabies. The shift of dog-maintained viruses into gray foxes, coyotes, skunks and other wild mesocarnivores throughout the Americas and to mongooses in the Caribbean has augmented the risk of human rabies exposures and has complicated control efforts. At the same time, the continued presence of bat rabies poses novel challenges in the absolute elimination of canine and human rabies. This article compiles existing historical and phylogenetic evidence of the origins and subsequent dynamics of rabies in the Western Hemisphere, from the era preceding the arrival of the first European colonizers through the present day. A companion article reviews the current status of canine rabies control throughout the Western Hemisphere and steps that will be required to achieve and maintain its complete elimination (Velasco-Villa et al., 2017).

Rocky Mountain spotted fever in Mexico: past, present, and future.

Rocky Mountain spotted fever, a tick-borne zoonosis caused by Rickettsia rickettsii, is among the most lethal of all infectious diseases in the Americas. In Mexico, the disease was first described during the early 1940s by scientists who carefully documented specific environmental determinants responsible for devastating outbreaks in several communities in the states of Sinaloa, Sonora, Durango, and Coahuila. These investigators also described the pivotal roles of domesticated dogs and Rhipicephalus sanguineus sensu lato (brown dog ticks) as drivers of epidemic levels of Rocky Mountain spotted fever. After several decades of quiescence, the disease re-emerged in Sonora and Baja California during the early 21st century, driven by the same environmental circumstances that perpetuated outbreaks in Mexico during the 1940s. This Review explores the history of Rocky Mountain spotted fever in Mexico, current epidemiology, and the multiple clinical, economic, and social challenges that must be considered in the control and prevention of this life-threatening illness.

Successful strategies implemented towards the elimination of canine rabies in the Western Hemisphere.

Almost all cases of human rabies result from dog bites, making the elimination of canine rabies a global priority. During recent decades, many countries in the Western Hemisphere have carried out large-scale dog vaccination campaigns, controlled their free-ranging dog populations and enforced legislation for responsible pet ownership. This article reviews progress in eliminating canine rabies from the Western Hemisphere. After briefly summarizing the history of control efforts and describing the approaches listed above, we note that programs in some countries have been hindered by societal attitudes and severe economic disparities, which underlines the need to discuss measures that will be required to complete the elimination of canine rabies throughout the region. We also note that there is a constant threat for dog-maintained epizootics to re-occur, so as long as dog-maintained rabies "hot spots" are still present, free-roaming dog populations remain large, herd immunity becomes low and dog-derived rabies lyssavirus (RABLV) variants continue to circulate in close proximity to rabies-naïve dog populations. The elimination of dog-maintained rabies will be only feasible if both dog-maintained and dog-derived RABLV lineages and variants are permanently eliminated. This may be possible by keeping dog herd immunity above 70% at all times, fostering sustained laboratory-based surveillance through reliable rabies diagnosis and RABLV genetic typing in dogs, domestic animals and wildlife, as well as continuing to educate the population on the risk of rabies transmission, prevention and responsible pet ownership. Complete elimination of canine rabies requires permanent funding, with governments and people committed to make it a reality. An accompanying article reviews the history and epidemiology of canine rabies in the Western Hemisphere, beginning with its introduction during the period of European colonization, and discusses how spillovers of viruses between dogs and various wild carnivores will affect future eradication efforts (Velasco-Villa et al., 2017).

The oldest case yet reported of osteoarthritis in a dog: an archaeological and radiological evaluation.

A century ago the remains of a dog skeleton were found in an archaeological double human burial, near Bonn-Oberkassel (Germany). Recent re-examination of the dog remains revealed that they were about 14,500 years old. Based on the growth plates, the animal was considered to be approximately 7·5 months old at the time of death. Based on the minimal humeral diameter, it was calculated that it was approximately 0·47 m tall at the shoulder and weighed approximately 15·7 kg. The right proximal ulna of this skeleton showed osteoarthritis, manifested by an osteophyte of 5×3×1·5 mm3 at its cranial edge, with no identified primary developmental causes for osteoarthritis. Osteochondritis dissecans, joint incongruity and trauma are possible aetiologies. The left ulna did not reveal any abnormalities.

Estimating the probability distribution of the incubation period for rabies using data from the 1948-1954 rabies epidemic in Tokyo.

Data of 98 rabies cases in dogs and cats from the 1948-1954 rabies epidemic in Tokyo were used to estimate the probability distribution of the incubation period. Lognormal, gamma and Weibull distributions were used to model the incubation period. The maximum likelihood estimates of the mean incubation period ranged from 27.30 to 28.56 days according to different distributions. The mean incubation period was shortest with the lognormal distribution (27.30 days), and longest with the Weibull distribution (28.56 days). The best distribution in terms of AIC value was the lognormal distribution with mean value of 27.30 (95% CI: 23.46-31.55) days and standard deviation of 20.20 (15.27-26.31) days. There were no significant differences between the incubation periods for dogs and cats, or between those for male and female dogs.

Canine Infections with Onchocerca lupi Nematodes, United States, 2011-2014.

Infections with Onchocerca lupi nematodes are diagnosed sporadically in the United States. We report 8 cases of canine onchocercosis in Minnesota, New Mexico, Colorado, and Florida. Identification of 1 cytochrome c oxidase subunit 1 gene haplotype identical to 1 of 5 from Europe suggests recent introduction of this nematode into the United States.

The Ancient Curse: Rabies.

A review of the global burden of rabies and the risk of exposure from leisure activities.

Canine rangeliosis due to Rangelia vitalii: from first report in Brazil in 1910 to current day - a review.

Canine rangeliosis (popular names: "nambi-uvú", i.e. ``bleeding ears''; "peste de sangue", i.e. ``bleeding plague''; and "febre amarela dos cães", i.e. ``yellow fever of dogs'') is a tick-borne haemolytic and haemorrhagic disease caused by the protozoan parasite Rangelia vitalii which infects erythrocytes, leukocytes, and endothelial cells of blood capillaries. Rangelia vitalii was first reported as a novel piroplasm of dogs in 1910 in Brazil, a discovery that was met with skepticism at that time. Canine rangeliosis has been diagnosed in domestic dogs not only in Brazil but also in other South American countries (Argentina and Uruguay). Rangelia vitalii infection has also been found incidentally in Brazil in wild dogs (Cerdocyon thous, the crab-eating fox). Despite the fact that researchers in the early 1900s suggested that R. vitalii was a hitherto unidentified piroplasm that would be transmitted by the tick Amblyomma aureolatum, it was not until 2012 that these hypotheses were actually confirmed by PCR and transmission studies. Molecular studies have shown that R. vitalii is related to the Babesia sensu strictu clade, but genetically different from other morphologically similar species of Babesia that infect dogs. Another difference between Babesia spp. and R. vitalii is the ability of R. vitalii to invade endothelial cells, erythrocytes, and leukocytes. Experimental infection in dogs has successfully reproduced the clinical picture and pathology of the natural disease. In this article, epidemiology, clinical signs, laboratory findings, pathogenetic mechanisms including oxidative stress and immune response, necropsy findings, microscopic lesions, diagnosis, and treatment of canine rangeliosis are reviewed. What is currently known about this protozoal disease since its first report over a century ago is presented herein.

Rabies in the Dutch East Indies a century ago - a spatio-temporal case study in disease emergence.

Rabies continues to spread through the Indonesian archipelago. During the past 20 years, several islands - including Flores, Ambon and Bali - that had historically been free of rabies have become infected. However, the Dutch East Indies (a Dutch colony that became modern Indonesia following World War II) had been infected since the 1880s. The spread of rabies is a lesson in the emergence of an infectious disease. Reports of human cases treated for rabies and livestock rabies cases from the 1880s to 1917 were compiled. The spatial and temporal distribution of these cases was analyzed using maps, spatial statistics and time-series techniques. The first confirmed case of rabies was reported in 1889 from the Batavia [Jakarta] district (although disease suspicion was reported as early as 1884). During the 1890s rabies was already commonly reported from Java and the east coast of Sumatra, and by the late 1890s, from Celebes [Sulawesi]. Between 1900 and 1916, cases were reported from other parts of Java, Sumatra and Sulawesi, and from Borneo, the Moluccas and other outlying islands. Between 1897 and 1916, a total of 8826 human cases treated for rabies were reported and between 1908 and 1917, 1033 livestock cases were reported. Most (97.5%) human cases treated were attributed to rabid dogs. Increasing numbers of reports were observed during the period. Between 1908 and 1916 the correlation between human and livestock case reports was 64.2%, and at the district level it was 75.9%. Moderate correlations (>40%) were found between human cases and livestock cases reported up to six months previously. Based on year of first report from each district, human cases were strongly clustered (Moran's autocorrelation 0.47, P=0.005). The most likely spatio-temporal cluster of reported cases of humans treated for rabies originated from the west coast of Sumatra between 1899 and 1905, and other clusters were identified in west Java (1898-1899), the district of Batavia and in east Java (1910-1911), Nusa Tengarra Barat (1912), Borneo (1914) and the east coast of Sumatra (1903-1906). Rabies was probably first introduced to the colonial capital of the Dutch Indies, Batavia [Jakarta] in the 1880s. It then spread rapidly throughout most of the archipelago during the next two to three decades because of the movement of dogs via the military forces, for trade and as pets, despite government regulations designed to control the epidemic. Such a history suggests that further emergence and reemergence of rabies in rabies-free islands will occur based on an island's location and position within the complex social, trade and transport network that represents the Indonesian archipelago. Targeted surveillance and enforcement of quarantine regulations remain critical, to prevent history repeating itself.

Zoonotic Onchocerca lupi infection in dogs, Greece and Portugal, 2011-2012.

Onchocerca lupi infection is reported primarily in symptomatic dogs. We aimed to determine the infection in dogs from areas of Greece and Portugal with reported cases. Of 107 dogs, 9 (8%) were skin snip-positive for the parasite. DNA sequences of parasites in specimens from distinct dog populations differed genetically from those in GenBank.

Progress towards eliminating canine rabies: policies and perspectives from Latin America and the Caribbean.

Human rabies transmitted by dogs is considered a neglected disease that can be eliminated in Latin America and the Caribbean (LAC) by 2015. The aim of this paper is to discuss canine rabies policies and projections for LAC regarding current strategies for achieving this target and to critically review the political, economic and geographical factors related to the successful elimination of this deadly disease in the context of the difficulties and challenges of the region. The strong political and technical commitment to control rabies in LAC in the 1980s, started with the regional programme coordinated by the Pan American Health Organization. National and subnational programmes involve a range of strategies including mass canine vaccination with more than 51 million doses of canine vaccine produced annually, pre- and post-exposure prophylaxis, improvements in disease diagnosis and intensive surveillance. Rabies incidence in LAC has dramatically declined over the last few decades, with laboratory confirmed dog rabies cases decreasing from approximately 25 000 in 1980 to less than 300 in 2010. Dog-transmitted human rabies cases also decreased from 350 to less than 10 during the same period. Several countries have been declared free of human cases of dog-transmitted rabies, and from the 35 countries in the Americas, there is now only notification of human rabies transmitted by dogs in seven countries (Bolivia, Peru, Honduras, Haiti, Dominican Republic, Guatemala and some states in north and northeast Brazil). Here, we emphasize the importance of the political commitment in the final progression towards disease elimination. The availability of strategies for rabies control, the experience of most countries in the region and the historical ties of solidarity between countries with the support of the scientific community are evidence to affirm that the elimination of dog-transmitted rabies can be achieved in the short term. The final efforts to confront the remaining obstacles, like achieving and sustaining high vaccination coverage in communities that are most impoverished or in remote locations, are faced by countries that struggle to allocate sufficient financial and human resources for rabies control. Continent-wide cooperation is therefore required in the final efforts to secure the free status of remaining countries in the Americas, which is key to the regional elimination of human rabies transmitted by dogs.

Parasitism of prehistoric humans and companion animals from Antelope Cave, Mojave County, northwest Arizona.

Previously, we reported a tick recovered from Antelope Cave in extreme northwest Arizona. Further analyses of coprolites from Antelope Cave revealed additional parasitological data from coprolites of both human and canid origin. A second tick was found. This site is the only archaeological locality where ticks have been recovered. We also discovered an acanthocephalan in association with Enterobius vermicularis eggs in the same coprolite. This association shows that the coprolite was deposited by a human. This discovery expands our knowledge of the range of prehistoric acanthocephalan infection. In addition, findings from canid coprolites of Trichuris vulpis are reported. This is the first published discovery of T. vulpis from a North American archaeological context. The close association of dogs with humans at Ancestral Puebloan (Anasazi) sites raises the potential that zoonotic parasites were transferred to the human population. The archaeological occupation is associated with the Ancestral Pueblo culture 1,100 yr ago.

Evolutionary history of dog rabies in Brazil.

Although dogs are considered to be the principal transmitter of rabies in Brazil, dog rabies had never been recorded in South America before European colonization. In order to investigate the evolutionary history of dog rabies virus (RABV) in Brazil, we performed a phylogenetic analysis of carnivore RABV isolates from around the world and estimated the divergence times for dog RABV in Brazil. Our estimate for the time of introduction of dog RABV into Brazil was the late-19th to early-20th century, which was later than the colonization period but corresponded to a period of increased immigration from Europe to Brazil. In addition, dog RABVs appeared to have spread to indigenous animals in Brazil during the latter half of the 20th century, when the development and urbanization of Brazil occurred. These results suggest that the movement of rabid dogs, along with human activities since the 19th century, promoted the introduction and expansion of dog RABV in Brazil.