Diseases from animals to humans

WELLNEWS

Victor Romulo Gallardo Dumaguing, MD

Zoonosis or zoonotic diseases are infectious diseases that humans acquire from animals sources.  They are transmitted by direct contact with the animal, by inhalation of their pulverized feces or excreta, or by injection of the pathogen or infectious agent by an arthropod, like a mosquito bite.
    Reservoirs of infection are either living hosts or inanimate objects or materials. Many pets are common reservoirs of infection, in which the microbe could be within the body of the animal without causing any illness or the animal’s body serve as an intermediate sanctuary for the development of the adult form of the pathogen.
    Dogs, cats, skunks, foxes, raccoons and other animals are known reservoir of the rabies virus, with bats being the most rabid.  The virus is transmitted to humans through the saliva that is introduced when one of these rabid animals bites a person. Aside from viruses, cats and dogs have been known to also transfer bacteria from their mouths into tissues where severe infection may result, which explains why, antibiotics are added to to anti-rabies regimen of people bitten by rabid animal. There is the so-called Cat-scratch disease in which a playful little abrasion from your favorite feline could lead to enlarged lymph nodes (kulani) all over the body whereas dogs have been known to spread fungal disease.
    Toxoplasmosis, a protozoan disease can be contracted by ingesting its oocysts from cat feces that are present in the litter boxes or sand boxes or cysts from raw or undercooked meats. Toxoplasmosis is extremely dangerous to the woman during the first three months of pregnancy, are frequently acquired by ingested with brain damage to the fetus. Typhoid fever and Salmonellosis, a severe diarrheal disease may be caused by ingesting the Salmonella typhosa bacteria in the feces of turtles, and maybe in the yolk of infected chicken eggs, a reality which made mothers flip the sunny-side up of breakfast egg to ensure safe and healthy eating for the family. There is also the so-called “mad cow’s disease” which is a severe neurological illness due to ingestion of beef from cows with bovine spongiform encephalopathy. Moreover, the food and mouth disease (FMD) that affects mostly children with rashes in their extremities, fingers and toes.  Thankfully, as of this writing, the pesky ASF =African swine fever- which pops up every now in then in different parts of the country, has not been shown to cause illness in humans.
    Notable animal- to- human disease transmission is exemplified by AIDS. Luc Montagnier of Pasteur Institute and Dr. John Gallo of CDC in Atlanta, share the honor and prestige of identifying the HIV-human immunodeficiency virus- as the cause of AIDS,; and that the virus came from a monkey in Subsaharan Africa. The ochre-orange monkey called Cercopithecus sabeus is a prized hunted animal of the natives who relish its raw brain which contained the virus. Psittacossis , also called ornithosis , is a disease with severe pulmonary and neurologic signs and symptoms due to inhalation of the pulverized droppings or feces of parrots, parakeets, pigeons or doves.
    Covid-19 is the cynosure of the entire world not so much for its endearing traits but for the dreadful fear it has spawned, leaving countless misery and death in its wake.  Thus, it’s prudent if we pause and take a look at the three highly pathogenic and deadly corona viruses; RNA viruses with a crown-like thorn on their surface, name derived from the Latin word for crown “ coronam”
    SARS-Cov 1 was discovered in Foshan China in November 2002 and spread to Hong Kong and later to Taiwan where its spread was contained but not after terrifying the whole world with its Severe Acute Respiratory Syndrome. Then in November 2012, another corona virus was identified in Jordan and spread to its neighboring countries in the region, thus giving rise to Middle East Respiratory Syndrome. On December 2019, an ophthalmologist in Wuhan China “detected” an unusual disease thought to be caused by a virus which later presented itself as SARS-CoV 2, the signs and symptoms of which, mostly respiratory are very severe with fatal outcomes, so worrisome that the WHO named the disease Covid 19 and declared it as pandemic in March 11, 2020.
    Infectious disease experts agree that viruses are the microbes that easily “jump” from their animal reservoir to humans. Another reality is that this contagion is easy where there are lots of wild animals waiting to be sold in wet markets. While there is no consensus, most experts think that the natural hosts of these viruses are bats, example Chinese horseshoe bat, with intermediary reservoir like the dromedary camel for the MERS-CoV, the palm civet for SARS-CoV 1 and even the pangolin for SARs-Cov2
    The writer is heartened by the encouraging positive feedback from our readers, mostly senior citizens, to them and Northern Philippine Times for kindly accommodating our articles, a BIG THANK YOU, MARAMING SALAMAT PO, STAY SAFE  GOD BLESS