M
- MAC (Mycobacterium avium Complex)
- Mad Cow Disease (BSE) — see Bovine Spongiform Encephalopathy
- Malaria
- Marburg Hemorrhagic Fever
- Marine Toxins
- MD (Muscular Dystrophy)
- MDR TB (Multidrug-Resistant TB)
- ME/CFS (Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome)
- Measles
- Measles Vaccination
- Melioidosis [Burkholderia pseudomallei Infection]
- Meningitis
- Meningococcal Disease
- Meningococcal Vaccination
- Mental Health
- Mental Health and Genetics
- see also Genetics and Genomics
- see also Mental Health
- MERS-CoV (Middle East Respiratory Syndrome Coronavirus)
- Methicillin Resistant Staphylococcus aureus — see MRSA
- Microalgal Bloom-associated Illness — see Harmful Algal Bloom (HAB)-Associated Illness
- Microcephaly
- see also Zika Virus Infection
- see also Zika Virus Infection and Pregnancy
- Micronutrient Malnutrition
- Microsporidia Infection
- Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
- see also Coronavirus (CoV)
- MMR Vaccination
- Molluscum Contagiosum
- Monkey B virus — see B virus Infection
- Monkeypox
- Mononucleosis, Infectious — see Epstein-Barr Virus Infection
- Motor Vehicle Injuries
- Mouse and Rat Control — see Rodents, Diseases from
- MRSA [Methicillin Resistant Staphylococcus aureus]
- Mucormycosis
- Mucus — see Cold, Common
- Multidrug-Resistant TB (MDR TB)
- Multiple organ dysfunction syndrome — see Sepsis
- Mumps
- Mumps Vaccination
- Murine (Flea-borne) Typhus — see Typhus Fevers
- Muscular Dystrophy (MD)
- Musculoskeletal Disorders — see Ergonomic and Musculoskeletal Disorders
- Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS)
- Mycobacterium abscessus Infection
- Mycobacterium avium Complex (MAC)
- Mycobacterium tuberculosis Infection — see Tuberculosis
- Mycoplasma pneumoniae Infection
- Mycotic diseases — see Fungal diseases
- Myelomeningocele — see Spina Bifida
- Myiasis