Corona virus

CORONAVIRUSES

Morphology Coronaviruses are enveloped; carrying petal or club-shaped or cro<al·like peplomer spikes giving appearance of solar corona • They are large (120-160 nm) spherical viruses having a helical symmetry. • lheypossess linear, positive-sensessRNA of26to32 kbp size, largest among !he non-segmemed RNA viruses. dasslfic.ation Coronaviridae family contains two sub families Corona-virinae and Torovirinae. llie former has been grouped into four genera-Alplu1coronavirus, Betacoronavirus, Gorn.-macoronouin,s and Deltocoronavlrt~~. Most of diem infect animals except Gammacoronavirus species, which are the padiogens of birds.

Human infection is unconunon except few who have adapted to human conditions. Fig. 49.2: Coronavirus (Petal or club shaped peplomers). Electron micrograph (arrows showing) Source IO!l 10270, Public Health Image Library, /Centers for Disease Control and Prevention lCOCJ,Atlanta/Dr. Fred Murphy; Sylvia Whitfield {wirhpennission) Human Coronavlrues lliere are six recognized Coronaviruses d1at are known to cause human infections; most of diem belong to Betocoronavirus except die fust two which belong to Alphacoronavir,~~.

I. Human coronavirus 229E

1. Human coronavirus NL63 (New Haven Coronavirus)
2. Human coronavirus OC<ll
3. Human coronavirus HKlJJ
4. SARS-CoV (Severe Acute respiratory syndrome coronavirus)
5. MERS-CoV (Middle East respiratory syndrome coronavirus). Most human coronaviruses are widespread affecting people of most part oft he world and produce mild upper respiratory tract infection and occasional diarrhea. Two exceptions are SARS-CoV and MERS-CoV which are geographically restricted, transmitted from man to man and have produced outbreaks of severe respiratory disease widi higher mortality.

SAR S-Co V (severe acute respiratory syndrome corona virus) • History: SARS was first recognized in China in 20()3 by WHO physician Dr. Carlo Urbani. Hediagnosed it in a businessman who had traveled from China, through Hong Kong, to Hanoi, Vietnam. The businessman and the doctor who first diagnosed SARS both died from the illness • Epidemiology: During 2003 outbreak, the SARS viru~ spread from Asia to various regions of the world causing nearly 8098 cases in 29 countries, with over 774 deaths. Hovvever, India remained free from the infection. Since 2004, no case has been reported from anywhere in the world . • Source: SARS-CoV infection in humans is believed to be contracted from animals, including monkeys, Himalayan palm civets, raccoon dogs, cat\ dogs, and rodents. • Clinical manifestation includes severe lower respiratory tract infection; characterized by muscle pain, headache, sore throat and fever, followed by the ons.et of respiratory symptoms. mainly cough, dyspnoea and pneumonia. MERS-<:oV (middle east respiratory syndromecoronavirus) MERS-CoV has recently caused a severe form of lower respiratory illness with a mortality of 30%. Epidemiology:ltwas first reported in Saudi Arabia in 2012. • Since then, several hundreds of cases have been reported from various countries located in and around the Arabian Peninsula such as Saudi Arabia, UAE, Qatar, Oman, Jordan, Kuwait, Yemen, Lebanon and Iran. • It is not reported from India yet. Source though unknown, it is believed to have been acquired from camels and bats. People at increased risk for MERS-CoVinfection include: • Recent history of travel from the Arabian Peninsula within 14 days • Close contacts of a confirmed case of MER$ • Healthcare personnel not using recommended infection control precautions • People with exposure to infected camels Clinkal manifestation • Incubation period is.about 2-14days. • Severe acute respiratory symptoms appear such as fever, cough and shortness of breath may appear. • Some people may develop gastrointestinal symptoms. including diarrhea a nc:I nausea/vomiting. • Complications such as pneumonia and kidney failure occur, especially in people with underlying co morbid conditions.

Currently in there is attack in Singapore and China