Zoonotic Diseases and Phytochemical Medicines for Microbial Infections in Veterinary Science: Current State and Future Perspective

Shin, Bora; Park, Woojun

According to the American Pet Products Association, the pet industry has expanded steadily at an average of 4% per year over the last two decades (24) . As a result, interest and research into pet-related zoonotic diseases is increasing. Common cat scratch disease is primarily caused by Bartonella henselae (25) . Although this Bartonella sp. can cause many types of animal infections, pets have been identified as notable reservoirs for human infection, implying a potentially high risk of humans (25) . Generally, B. bacilliformis and B. quintana are considered human-specific pathogens, but several zoonotic Bartonellae spp. specific to diverse animal hosts can also infect humans as incidental hosts (25, 26) . Pathogenic Bartonella spp. are endotheliotropic bacteria with a distinctive mechanism for invasion into host cells involving the injection of peptides and transport of bacterial DNA into the cells; these species can move by infecting macrophages (26) . Recently, significant associations have been found between amino acid alleles of Toll-like receptors and susceptibility to infection with the blood pathogenic and clinically isolated Bartonella sp. Cat fleas, sand flies, human body lice, and many other flea species can transmit certain Bartonella spp. (14, 26) . It has been reported that in addition to pets, other animals, including rodents, cattle, deer, and sheep, can spread Bartonella infection through flies or deer keds (Lipoptena cervi) (27) . Most cases of cat scratch disease get cured without treatment; however, some immunocompromised patients can present complications from disseminated diseases (25) . Bartonella spp. can cause acute or chronic infection with vascular proliferative or suppurative manifestations. Blood culture-negative endocarditis and bacteremia can also be induced by a spectrum of Bartonella spp. in canine and human patients (15) . Numerous antibiotics, including azithromycin, penicillin, tetracyclines, cephalosporins, and aminoglycosides, are effective against Bartonella infection (25, 26) . Doxycycline, amoxicillin, enrofloxacin, and rifampin given for a long duration (more than 4 weeks) may effectively reduce the level of bacteremia in an infected cat or dog, although there is a risk of side effects (25) .