It would be highly unlikely to be infected via casual fighting or contacts sports.
Pathogens can infect humans through inhalation of respiratory droplets, contact with contaminated surfaces and objects, ingestion of contaminated food or water, and through bites from infected animals.
HIV is ONLY transmitted through contact with infected blood, semen, vaginal fluid or breast milk. All other body fluids do not contain an adequate amount of HIV to infect another person.
right away
Only if you are going through an outbreak, this is when the sores are discharging and can infect others by contact.
Part of the reason is the difference in size. Another is that we consume bacteria but not actually infect them. It is a matter of terminology.
Hazards that have the potential to infect others include pathogens such as bacteria, viruses, and fungi. These can be transmitted through contact with infected individuals, contaminated surfaces, or through the air. It's important to practice proper hygiene, sanitation, and infection control measures to prevent the spread of these hazards.
Microorganisms have several avenues in which they can infect larger organisms. They can enter the body through any of the body's natural openings, through wounds or injection and some can even cause infections through skin contact.
Viruses only infect living organisms and since they are not alive, they can not infect other viruses. The question is interesting though.
Schistosomiasis is caused by parasitic worms called Schistosoma. These worms infect humans through contact with contaminated water sources where the parasites live.
YES
In that one person is infected by another, then infects a third person, who then goes on to infect another person, yes, HIV is a chain reaction. It is spread through human conctact and transmission of the virus through the blood and body fluids.