The Ebola epidemic in West Africa is certainly no laughing matter and the first cases to receive publicity outside of Africa have created a media frenzy, and a twist applicable to animal owners’ interests have emerged with dogs in Dallas and Spain being potentially exposed and raising concerns from animal owners. What if I told you that there is a disease endemic in North Texas (as well as other parts of the country and the world) , a viral disease, almost 100% fatality rate in any species, affects humans, dog bites in Asia and Africa cause tens of THOUSANDS of deaths in Asia and Africa every year, and millions more deaths are prevented each year through post exposure vaccination? The disease affects wild animals as well as domestic farm animals and is transmitted by infected animals biting or contaminating open areas or mucous membranes with saliva. Make Ebola sound a little less threatening? Our old nemesis RABIES has been amongst us and it will be interesting to see if Ebola or rabies claims more lives this year. Remember, you can protect both you and your animals by vaccinating your animals every one to three years, depending on laws and species, and the vaccine remains extremely effective in maintaining the safety of both our animal and human population. Most everyone has learned to recognize the likely rabid animal and what to do to protect one’s self and others from a threat. I have all the confidence in the world that between our modern medical technology and information dissemination technologies, Ebola will be another manageable threat to humanity that we learn to live with and overcome. Below are my notes from the show and what research has been accumulated on Ebola in animals during its tenure in Africa, Thanks for stopping by!
Dev Biol (Basel). 2013;135:211-8. doi: 10.1159/000178495. Epub 2013 May 14.
Review of Ebola virus infections in domestic animals.
Weingartl HM1, Nfon C, Kobinger G.
Ebola viruses (EBOV; genus Ebolavirus, family Filoviridae) cause often fatal, hemorrhagic fever in several species of simian primates including human. While fruit bats are considered a natural reservoir, the involvement of other species in the EBOV transmission cycle is unclear, especially for domesticated animals. Dogs and pigs are so far the only domestic animals identified as species that can be infected with EBOV. In 2009 Reston-EBOV was the first EBOV reported to infect swine with indicated transmission to humans; and a survey in Gabon found over 30% seroprevalence for EBOV in dogs during the Ebola outbreak in 2001-2002. While infections in dogs appear to be asymptomatic, pigs experimentally infected with EBOV can develop clinical disease, depending on the virus species and possibly the age of the infected animals. In the experimental settings, pigs can transmit Zaire-Ebola virus to naive pigs and macaques; however, their role during Ebola outbreaks in Africa needs to be clarified. Attempts at virus and antibody detection require as a prerequisite validation of viral RNA and antibody detection methods especially for pigs, as well as the development of a sampling strategy. Significant issues about disease development remain to be resolved for EBOV. Evaluation of current human vaccine candidates or development of veterinary vaccines de novo for EBOV might need to be considered, especially if pigs or dogs are implicated in the transmission of an African species of EBOV to humans
Emerg Health Threats J. 2012;5. doi: 10.3402/ehtj.v5i0.9134. Epub 2012 Apr 30.
Dead or alive: animal sampling during Ebola hemorrhagic fever outbreaks in humans.
Olson SH1, Reed P, Cameron KN, Ssebide BJ, Johnson CK, Morse SS, Karesh WB, Mazet JA, Joly DO.
There are currently no widely accepted animal surveillance guidelines for human Ebola hemorrhagic fever (EHF) outbreak investigations to identify potential sources of Ebolavirus (EBOV) spillover into humans and other animals. Animal field surveillance during and following an outbreak has several purposes, from helping identify the specific animal source of a human case to guiding control activities by describing the spatial and temporal distribution of wild circulating EBOV, informing public health efforts, and contributing to broader EHF research questions. Since 1976, researchers have sampled over 10,000 individual vertebrates from areas associated with human EHF outbreaks and tested for EBOV or antibodies. Using field surveillance data associated with EHF outbreaks, this review provides guidance on animal sampling for resource-limited outbreak situations, target species, and in some cases which diagnostics should be prioritized to rapidly assess the presence of EBOV in animal reservoirs. In brief, EBOV detection was 32.7% (18/55) for carcasses (animals found dead) and 0.2% (13/5309) for live captured animals. Our review indicates that for the purposes of identifying potential sources of transmission from animals to humans and isolating suspected virus in an animal in outbreak situations, (1) surveillance of free-ranging non-human primate mortality and morbidity should be a priority, (2) any wildlife morbidity or mortality events should be investigated and may hold the most promise for locating virus or viral genome sequences, (3) surveillance of some bat species is worthwhile to isolate and detect evidence of exposure, and (4) morbidity, mortality, and serology studies of domestic animals should prioritize dogs and pigs and include testing for virus and previous exposure.
Domestic animal sampling
Efforts targeting domestic animals (cow, goat, sheep, pig, and dog) represented 0.9% (114/13,404) of all samples in the collection (Appendix C). With the exception of one goat carcass, all were live samples, and all samples tested negative for EBOV (Appendix A, B, and C). Only dog samples were tested for EBOV antibody, which was detected at 26.3% (21/80) prevalence. Conversely, the overall antibody detection prevalence was 2.0% (159/7,960) for wild species (Appendix A). The 80 dog (Canis lupus familiaris) samples were collected during two sampling efforts associated with human outbreaks in Democratic Republic of Congo (DRC) 1979–1980 and Gabon 2001–2002 (Appendix A). The 12 pig (Sus scrofa) samples tested were collected during the DRC Yambuku 1976 and DRC Kikwit 1995 human outbreaks (Appendix B).
Non-human primate susceptibility to EBOV was evident in the scientific literature. EBOV belongs to the same virus family as Marburgvirus, and a Marburg hemorrhagic fever outbreak had been linked to green monkeys (Chlorocebus aethiops) 9 years prior to the first recognized EHF outbreak in Yambuku, DRC (22). However, it was not until the early nineties that evidence again hinted that non-human primates provided a transmission link between the sylvatic cycle of the virus and human outbreaks. Late in 1989 outbreaks of REBOV, at that time a new strain of EBOV, occurred in non-human primate quarantine centers in the United States, putatively killing monkeys (Macaca fascicularis) imported from the Philippines and causing seroconversion but no disease in humans who handled the monkeys (23–25). In November 1994 a natural outbreak of EHF occurred in chimpanzees (Pan troglodytes) in Taï National Park, Côte d’Ivoire, and a researcher who necropsied an ape carcass became infected with another new subtype of EBOV, Côte d’Ivoire ebolavirus (CIEBOV) (26). Around that same time in Gabon a set of three human EHF outbreaks began that coincided with deaths of non-human primates. The index human cases of the last outbreak in Gabon, in the spring of 1996, had a history of butchering chimpanzees. A chimpanzee carcass found near the hunting grounds of an index case tested positive for EBOV by an immunohistochemical skin biopsy (27).
Many dog owners feel like their pets are like their children — and your brain seems to think so, too. In a new study published in the journal PLOS ONE, researchers at Massachusetts General Hospital investigated differences in brain activity when women volunteers viewed pictures of their dogs, their children, and unfamiliar dogs and children. What they found suggests that the bond between human and pup tugs at some of the same heartstrings — or rather, brainstrings — as the bond between mother and child.
The MGH team analyzed functional MRI data for 14 women, each with at least one child between two and 10 years old and a pet dog that had been owned for at least two years. In the course of the experiment, the women were shown a series of photographs: of their child, of their dog, and of unfamiliar dogs and children. The MRI machine paints a portrait of the participants’ brain activity while viewing the images, by detecting changes in blood flow and oxygen levels in different brain structures.
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The MRI data showed “substantial overlap in brain activation patterns in regions involved in reward, emotion, and affiliation elicited by images of both a mother’s own child and dog,” the authors wrote. But there were some key differences: Photos of a woman’s own child elicited a response in a brain region called the substantia nigra/ventral tegmental area, linked to bond formation; photographs of a beloved dog did not provoke a response there. But pictures of a woman’s own dog sparked greater activity in the fusiform gyrus, a brain structure involved in facial recognition, than even pictures of a person’s own child. The researchers think this might stem from the fact that with dogs, people rely much more on visual cues than the verbal communication they have with children.
“These results demonstrate that the mother-child and mother-dog bond share aspects of emotional experience and patterns of brain function, but there are also brain-behavior differences that may reflect the distinct evolutionary underpinning of these relationships,” the authors wrote.
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So, basically: Your brain’s bond with your dog is somewhat similar to your bond with your child, but not exactly the same.
Other scientists have explored the human-dog relationship from the canine point of view. Neurobiologists in Budapest used brain scanners to investigate how dogs detect emotions in both human and dog vocalizations (training the canines to get in the MRI scanner and hold still was a job in and of itself); they discovered that there are, indeed dog brain regions that light up preferentially when hearing human or dog emotional cues. And a group of veterinary scientists from Viennafound that dogs, like young children, are much more eager to explore new environments with their caregiver around — something that in child psychology is called the “secure base effect.”
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The MGH team notes that their latest study is just a small sample; it remains to be seen if the same brain activity patterns they saw in this group of dog owners would show up in women without children, women with adopted children, men, or in cat owners — although in this last case, the scientific literature suggests that affection might be a one-way street.
Table: Categories of contact and recommended post-exposure prophylaxis (PEP)
Categories of contact with suspect rabid animal Post-exposure prophylaxis measures
Category I – touching or feeding animals, licks on intact skin None
Category II – nibbling of uncovered skin, minor scratches or abrasions without bleeding Immediate vaccination and local treatment of the wound
Category III – single or multiple transdermal bites or scratches, licks on broken skin; contamination of mucous membrane with saliva from licks, contacts with bats. Immediate vaccination and administration of rabies immunoglobulin; local treatment of the wound
All category II and III exposures assessed as carrying a risk of developing rabies require PEP. This risk is increased if:
• the biting mammal is a known rabies reservoir or vector species;
• the animal looks sick or has an abnormal behaviour;
• a wound or mucous membrane was contaminated by the animal’s saliva;
• the bite was unprovoked; and
• the animal has not been vaccinated.
In developing countries, the vaccination status of the suspected animal alone should not be considered when deciding whether to initiate prophylaxis or not.
Local treatment of the wound
Removing the rabies virus at the site of the infection by chemical or physical means is an effective means of protection. Therefore, prompt local treatment of all bite wounds and scratches that may be contaminated with rabies virus is important. Recommended first-aid procedures include immediate and thorough flushing and washing of the wound for a minimum of 15 minutes with soap and water, detergent, povidone iodine or other substances that kill the rabies virus.
No tests are available to diagnose rabies infection in humans before the onset of clinical disease, and unless the rabies-specific signs of hydrophobia or aerophobia are present, the clinical diagnosis may be difficult. Human rabies can be confirmedintra-vitam and post mortem by various diagnostic techniques aimed at detecting whole virus, viral antigens or nucleic acids in infected tissues (brain, skin, urine or saliva).
People are usually infected following a deep bite or scratch by an infected animal. Dogs are the main host and transmitter of rabies. They are the source of infection in all human rabies deaths annually in Asia and Africa.
Bats are the source of most human rabies deaths in the Americas. Bat rabies has also recently emerged as a public health threat in Australia and western Europe. Human deaths following exposure to foxes, raccoons, skunks, jackals, mongooses and other wild carnivore host species are very rare.
Transmission can also occur when infectious material – usually saliva – comes into direct contact with human mucosa or fresh skin wounds. Human-to-human transmission by bite is theoretically possible but has never been confirmed.
Rarely, rabies may be contracted by inhalation of virus-containing aerosol or via transplantation of an infected organ. Ingestion of raw meat or other tissues from animals infected with rabies is not a source of human infection.
• Rabies is a vaccine-preventable viral disease which occurs in more than 150 countries and territories.
• Infection causes tens of thousands of deaths every year, mostly in Asia and Africa.
• 40% of people who are bitten by suspect rabid animals are children under 15 years of age.
• Dogs are the source of the vast majority of human rabies deaths.
• Immediate wound cleansing and immunization within a few hours after contact with a suspect rabid animal can prevent the onset of rabies and death.
• Every year, more than 15 million people worldwide receive a post-exposure vaccination to prevent the disease – this is estimated to prevent hundreds of thousands of rabies deaths annually
situation in Liberia is scary, and might be spiralling out of control.
Ebola cases in West Africa
The total number of cases is rising at an exponential rate. As of 14 September, the doubling time is 16 days in Guinea, 24 days in Liberia and 30 days in Sierra Leone .
Ebola cases in West Africa (Data: WHO / Chart CC BY 4.0: JV Chamary / Source: http://onforb.es/1sCVxE1)
In epidemiology, the speed at which an infectious agent spreads is measured by its reproductive number, ‘R’ – the average number of new cases created by infectious individuals exposed to a susceptible population. When R is greater than 1, the chain of transmission is sustained as each primary case produces at least one secondary case.
At the start of an outbreak, the rate is called ‘R0′ (the basic reproductive number). R0 indicates whether or not a contagious disease has the potential to become an epidemic. Populations can evolve natural immunity or gain artificial protection through health interventions like vaccination, reducing the proportion of susceptible people, so the reproductive number for later periods of time is ‘Rt’.
R0 was 1.7 to 2 during the initial period of exponential growth in West Africa, while the current Rt is 1.4-1.8 . (Calculations by the WHO Ebola Response Team are roughly in line with estimates by other researchers.) R = 2 doesn’t sound high until you hear that the deadliest pandemic in recorded history, the 1918 Spanish flu, killed up to 100 million people even though the influenza virus had an R of 2.
If public health authorities can lower the reproductive number of Ebola below the critical value of 1, the current epidemic will eventually fizzle-out.