Human population growth serves as an important model for population ecologists, and is one of the most important environmental issues of the twenty-first century.
Fluids that Spread Bloodborne Pathogens. The transmission of bloodborne pathogens from one person to another occurs through the transfer of infected body fluids. Common body fluids which can transmit pathogens include: blood. cerebral spinal fluid. semen. vaginal secretions.
1 When they enter your system through water, they cause cholera; when it is through food, then they cause salmonella.  Through Body Fluids: Pathogen can infect you by entering your body through semen and blood. Some of the most common examples of pathogens that spread through body fluids are hepatitis and HIV viruses.