Patogenic

Patogenic is not the standard English term for this concept. The correct term is pathogenic, meaning capable of causing disease. It can describe organisms (pathogens) or agents such as bacteria, viruses, fungi, and parasites, as well as toxins or other molecules that produce disease. The word derives from Greek pathos (suffering, disease) and -genic (producing). In English, patogenic is typically a misspelling; in some languages or historical contexts it may appear, but pathogenic is the accepted form.

Pathogenicity refers to the ability to cause disease, which depends on factors in both the agent and the host. Pathogenic organisms possess virulence factors that facilitate infection, colonization, tissue invasion, toxin production, and evasion of host immunity. Examples include adhesins for attaching to cells, invasins for entering tissues, capsules for resisting phagocytosis, and toxins that disrupt cellular function. The degree of disease-causing potential, virulence, varies widely among pathogens and can be quantified by measures such as ID50 (infectious dose) or LD50 (lethal dose).

Pathogens interact with hosts in complex ways. Host range and tissue tropism determine where an agent can replicate. Disease may result from direct tissue damage, immune-mediated injury, or metabolic disruption. Many agents are opportunistic, causing disease primarily in individuals with weakened defenses.

Transmission routes include direct contact, respiratory droplets, sexual contact, vectors, and environmental reservoirs. Prevention and control rely on vaccination, hygiene, antimicrobial therapies, infection-control practices, and surveillance.

Examples of pathogenic agents include bacteria such as Mycobacterium tuberculosis, viruses such as influenza, fungi such as Candida albicans, and parasites such as Plasmodium species. Pathogenicity remains a central concept in medicine, microbiology, and public health.