the population can increase rapidly when the conditions are favourable. it is more time and energy efficient as you don’t need a mate. it is faster than sexual reproduction.

Asexual reproduction yields genetically-identical organisms because an individual reproduces without another. In sexual reproduction, the genetic material of two individuals from the same species combines to produce genetically-different offspring; this ensures mixing of the gene pool of the species.

Some animals produce offspring through asexual reproduction while other animals produce offspring through sexual reproduction. In a stable or predictable environment, asexual reproduction is an effective means of reproduction because all the offspring will be adapted to that environment.

The math is simple: with four asexual adults (females) you get eight offspring, but with two males and two females you get only four offspring. In other words, the asexual population grows twice as fast as the sexually reproducing one.

The simplest way for such a particle to pass through the single lipid bilayer that separates it from the outside of the cell would be to violate the integrity of that bilayer. Thus, it is not surprising that the primary mode of exit for non-enveloped viruses is cell lysis.

NA is the second most abundant (∼17%) envelope protein and forms the tetrameric spikes. NA removes the cell surface receptor (sialic acid) and plays a critical role in the release of progeny virus particles from the cell surface as well as the spread and transmission of virus from host to host.

The influenza virus life cycle can be divided into the following stages: entry into the host cell; entry of vRNPs into the nucleus; transcription and replication of the viral genome; export of the vRNPs from the nucleus; and assembly and budding at the host cell plasma membrane.

All influenza viruses encode the polymerase subunit PB1 on segment 2; in some strains of influenza A virus, this segment also codes for the accessory protein PB1-F2, a small, 87-amino acid protein with pro-apoptotic activity, in a +1 alternate reading frame [3].

Regardless of the virion shape, HA is the most abundant viral envelope protein, followed by NA, and M2 (30). Recent work has shown that the viral envelope also contains host membrane proteins (30, 31).

When the influenza virus propagates inside our body, a lot can change during the process, because the genetic material of the virus mutates very easily.

The structure of the influenza virus (see Figure 1) is somewhat variable, but the virion particles are usually spherical or ovoid in shape and 80 to 120 nanometers in diameter. Sometimes filamentous forms of the virus occur as well, and are more common among some influenza strains than others.

Unlike type A flu viruses, type B flu is found only in humans. Type B flu may cause a less severe reaction than type A flu virus, but occasionally, type B flu can still be extremely harmful. Influenza type B viruses are not classified by subtype and do not cause pandemics.

Common signs of an influenza infection include:

• coughing.
• runny or stuffy nose.
• sneezing.
• sore throat.
• fever.
• headache.
• fatigue.
• chills.

Type A influenza is generally considered worse than type B influenza. Flu or influenza is a contagious (spreads from person to person) viral illness that affects the respiratory tract (the nose, throat and lungs). Flu infections are more common during the fall and winter.

Influenza B Strain Dominating Early in the 2020 Flu Season.

COVID-19 is a contagious respiratory illness caused by the SARS-CoV-2 virus. COVID-19 can cause a mild to severe illness and has now spread worldwide, including in the United States.

The time from exposure to symptom onset (known as the incubation period) is thought to be two to 14 days, though symptoms typically appear within four or five days after exposure. We know that a person with COVID-19 may be contagious 48 hours before starting to experience symptoms.

People with flu are most contagious in the first 3-4 days after their illness begins. Some otherwise healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick.

For most healthy people, the flu is an uncomfortable but short-term illness that resolves itself as the immune system fights it off. Symptoms usually appear from one to four days after exposure to the virus, and they last five to seven days.

Influenza A viruses are found in many different animals, including ducks, chickens, pigs, whales, horses, seals and cats. Influenza B viruses circulate widely only among humans.