Reverse zoonosis. How human pathogens affect animals.

Reverse zoonosis. The fact that diseases can pass from humans to animals is, perhaps, not such a surprise. An estimated 61.6 percent of human pathogens are regarded as multiple species pathogens and are able to infect a range of animals.

 Also, over 77 percent of pathogens that infect livestock are multiple species pathogens. One of the earliest studies demonstrating reverse zoonosis was conducted in 1988 and looked at dermatophytes - fungi that cause superficial infections of the skin, nails, and hair - including Microsporum and Trichophyton.

The authors found that these fungi could be transmitted from animal to animal, human to human, animal to human, and human to animal.

 From 2000, studies began to emerge investigating the ability of certain parasites to pass from human to animal, including Giardia duodenalis (the parasite responsible of giardiasis), and Cryptosporidium parvum (a microscopic parasite that causes the diarrheal disease cryptosporidiosis) A CASE OF .Reverse zoonosis. 

 A study, published in the journal Veterinary Microbiology in 2006, looked at methicillin-resistant Staphylococcus aureus (MRSA) in pets and its transmission between humans and animals.The paper mentions a specific case in which a couple was repeatedly infected with MRSA.

The re-infections only stopped once their dog was identified as the source and treated. It is presumed that the dog was initially infected by the couple and then passed the infection back to them each time they had been successfully treated.

 The emergence of MRSA in household pets is of concern in terms of animal health and the potential for animals to act as sources of infection or colonization of human contacts.Reverse zoonosis.

 A paper, published in 2004, describes the case of a 3-year-old Yorkshire terrier who arrived at the University of Tennessee College of Veterinary Medicine with anorexia, vomiting, and a persistent cough. After running a barrage of tests - including, sadly, an eventual postmortem - the authors concluded that it had contracted tuberculosis (TB) (Mycobacterium tuberculosis).

The dog's owner had been receiving treatment for TB for 6 months. This was the first documented transmission of TB from human to canine.

 In 2009, the first recorded case of fatal human-to-cat transmission of the H1N1 flu virus occurred in Oregon. The owner of the cat had a severe case of influenza and had to be taken to the hospital. Her cat - an indoor cat with no exposure to other people or animals - later died of pneumonia caused by an H1N1 infection.
Details of the case were published in the journal Veterinary Pathology. In 2011 and 2012, researchers identified more than 13 cats and one dog with pandemic H1N1 infection that appeared to have come from human contact. Interestingly, the animals' symptoms were similar to those experienced by human carriers - rapidly developing respiratory disease, a lack of appetite and, in some cases, death.

Scientists find how 'superbugs' build their defenses.

Scientists in Britain have found how drug-resistant bacteria build and maintain a defensive wall — a discovery that paves the way for the development of new drugs to break through the barrier and kill the often deadly “superbugs”. In recent decades, bacteria resistant to multiple drugs, such as methicillin-resistant Staphylococcus aureus (MRSA) or Clostridium difficile, have grown into a global health threat, while superbug strains of infections like tuberculosis and gonorrhoea have become untreatable. The World Health Organization has warned that many antibiotics could become redundant this century, leaving patients vulnerable to deadly infections and threatening the future of medicine. Researchers publishing a study in the journal Nature on Monday said knowing the mechanism bacteria use to keep up their defences brings scientists closer to solving the problem of antibiotic resistance, since new treatments can be designed to weaken those defences rather than attack the bacteria directly. This means that in future, bacteria may not develop drug-resistance at all, they said. The team led by Changjiang Dong, a professor at Britain’s University of East Anglia, used a machine called Diamond Light Source — which produces intense light 10 billion times brighter than the sun — to investigate in tiny detail a class of bugs known as Gram-negative bacteria. Gram-negative bacteria are particularly resistant to antibiotics because their cells have an impermeable lipid-based outer membrane which acts as a defensive barrier against attacks from the body’s immune system and from antibiotic drugs. Dong’s team zeroed in on the defensive wall and found that it is built and maintained by what they described as a beta-barrel assembly machinery (BAM) containing five sub-units called BamA, BamB, BamC, BamD and BamE. They then figured out how these sub-units work together to form and maintain the cell membrane, and crucially, how to disrupt that mechanism. “The beta-barrel assembly machinery is responsible for building the ‘gates’ in the cell wall,” Dong explained. “Stopping the beta-barrel assembly machine from building the gates in the cell wall cause the bacteria to die.” The study found that the sub-unit BamA, which is found in the outer membrane and exposed to the outer side of the bacteria, is a key component of the mechanism — making it “a great target” for new drugs, Dong’s team said.

ANTIMICROBIAL RESISTANCE IN HORSES.

The use of antimicrobial s in food animals have been linked to the emergence of antibiotic resistance in man and animals as well.The emergence of the super bugs has been the light on the way food animals are raised and managed,with people clamoring for antibiotic-free livestock production.Antibiotics in livestock should be used as treatment protocol and not as growth promoters in animals,because these residues do more harm to man that consume these animals.These antibiotic residues have been linked to several ailments plaguing man today. The antibiotic resistance war has enveloped the companion animals as well as other pets, a lot of pet lover/owners and handlers abuse the use of antibiotics as well resulting in resistance which affects their owners as well.The E.coli infection affecting man and animals are borne from gross misuse of antibiotics ; a recent study shows the resistance in horses; new review in the Equine Veterinary Journal reveals that antimicrobial resistance is prevalent in bacteria from horses, particularly E. coli. Also, while methicillin-resistant S. aureus (MRSA) can be common in hospitalized horses, it is less frequently present in the general equine population. The emergence of multidrug resistance in many other bacterial species, however, represents a huge challenge for society. Read more here http://www.sciencedaily.com/releases/2015/11/151120182819.htm