CDC tracks COVID-19 illnesses, hospitalizations, and deaths to monitor trends, detect where outbreaks are occurring, and determine whether public health measures are working. However, counting exact numbers of COVID-19 cases is not possible because COVID-19 can cause mild illness, symptoms might not appear immediately, there are delays in reporting and testing, not everyone who is infected gets tested or seeks medical care, and there are differences in how completely states and territories report their cases.

There is no evidence that COVID-19 can spread to people through water, including floodwater. Sometimes floodwater can mix with wastewater. CDC is not aware of any scientific reports of the virus being spread by swallowing or coming in contact with water contaminated by feces from an infected person.

Viruses are named based on their genetic structure to facilitate the development of diagnostic tests, vaccines and medicines. Virologists and the wider scientific community do this work, so viruses are named by the International Committee on Taxonomy of Viruses (ICTV).

A pandemic is defined as “an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people”. The classical definition includes nothing about population immunity, virology or disease severity. By this definition, pandemics can be said to occur annually in each of the temperate southern and northern hemispheres, given that seasonal epidemics cross international boundaries and affect a large number of people. However, seasonal epidemics are not considered pandemics.

‘CO’ stands for corona, ‘VI’ for virus, and ‘D’ for disease. Formerly, this disease was referred to as ‘2019 novel coronavirus’ or ‘2019-nCoV.’ The COVID-19 virus is a new virus linked to the same family of viruses as Severe Acute Respiratory Syndrome (SARS) and some types of common cold.

All available evidence for COVID-19 suggests that SARS-CoV-2 has a zoonotic source.