"THE CHAIN LETTER" (1)is a disease-causing organism which includes bacteria, virus, parasitic worm,
protozoa, and fungi and lives in the ( 2 )which can be a living or non-living object. In
order to be transmitted, the pathogen leaves the reservoir through the (3)Examples include the mouth, nose, anus, and other special body openings. The pathogen is thenpassed through a direct or indirect (4)from one host to the next host. It is transmitted through a living vector like a mosquito or flea. Some diseases like malaria have complicated life cycles involving more than one species. Some are transmitted by respiratory droplets, while others are through blood contact, semen or other secretions. Hand-to-mouth is a common mode for gastrointestinal pathogens. The organism enters the body through the(5)such as the nose, skin, or mouth. The portal of entry determines the type of personal protective equipment (PPE) to use to keep health care workers, family and visitors safe in the hospital. The (6)is a person with low immunity to disease. This includes the very old, and the immune suppressed (due to genetics, transplant drugs, malnutrition, or viral infection like HIV).​