2.1 How Disease and Infection Are Caused and Transmitted
Key Takeaways
- NIC New Jersey Domain 1.A.1 tests how disease and infection are caused and transmitted by bacteria, viruses, fungi, and parasites.
- Direct transmission is person-to-person; indirect transmission uses a contaminated tool, towel, or surface; airborne and respiratory droplets ride coughs, sneezes, and talk.
- Staphylococci (including MRSA) are the pus-forming bacteria most associated with contaminated implements; bacterial spores survive ordinary cleaning and require sterilization.
- N.J.A.C. 13:28-3.2(a)3 requires an EPA-registered disinfectant labeled as tuberculocidal, or an FDA-registered autoclave, because tuberculosis is a hard-to-kill airborne bacterial benchmark.
- New Jersey shops break the chain by refusing contagious services, processing or discarding tools under N.J.A.C. 13:28-3, and using hand hygiene after every patron.
2.1 How Disease and Infection Are Caused and Transmitted
The NIC New Jersey Cosmetologist-Hair Stylist theory examination is 120 items, of which 110 are weighted, in 120 minutes. Domain 1, Scientific Concepts, is 30 of those weighted items. Domain 1.A opens with a competency that later questions keep using: identify how disease and infection are caused and transmitted. New Jersey does not leave that science in a textbook. Licensed shops operate under N.J.A.C. 13:28 Subchapter 3, Safety and Sanitation, issued for shops regulated by the New Jersey State Board of Cosmetology and Hairstyling. The 1,200-hour curriculum in N.J.A.C. 13:28-6.29 assigns 20 hours to decontamination and infection control (15 class, 5 practical). If you cannot name the organism and the route, you will miss both the NIC science item and the shop-rule item.
Infection, disease, and contamination
Infection is the invasion of body tissue by disease-causing organisms. Disease is the resulting abnormal condition of the body. Contamination is soil, blood, or microbes on a tool, surface, or skin that should be clean. A contaminated shear is already a problem even if the next client never develops a visible infection. The shop's legal duty is to interrupt that chain on every client, not after someone files a complaint.
A pathogen is an organism capable of causing disease. Four groups appear on this exam: bacteria, viruses, fungi, and parasites. Nonpathogenic organisms are harmless or even beneficial. Pathogenic organisms produce toxins, pus, or tissue damage.
Bacteria
Bacteria are one-celled microorganisms. They live on skin, in water, in product residue, and on implements that were not processed after the last client.
| Group | Shape | Salon-relevant examples |
|---|---|---|
| Cocci | Round | Staphylococci (clusters): pus, abscesses, boils, MRSA. Streptococci (chains): strep throat, blood poisoning. Diplococci (pairs): pneumonia |
| Bacilli | Rod | Tetanus, typhoid fever, tuberculosis; many move with flagella |
| Spirilla | Spiral or corkscrew | Syphilis (Treponema pallidum), Lyme disease (Borrelia burgdorferi) |
Staphylococci are the bacteria to picture on a dirty implement. They produce pus and local infections such as abscesses and boils. MRSA (methicillin-resistant Staphylococcus aureus) is a staph strain that does not yield to many common antibiotics. It still spreads the ordinary way: skin contact and contaminated tools. A New Jersey licensee does not MRSA-test a comb. The licensee cleans and then applies an EPA-registered tuberculocidal disinfectant or an FDA-registered autoclave, or discards the item, every time.
A local infection stays in one area (a pimple, a boil). A systemic, or general, infection travels in the bloodstream. Bacterial spores are a dormant, highly resistant form. Ordinary cleaning does not destroy spores. That is why the CIB treats sterilization as its own level, and why N.J.A.C. 13:28-3.2(a)3 lists an FDA-registered autoclave as a lawful alternative to chemical disinfection.
Viruses
A virus is a submicroscopic particle that infects a host cell and replicates there. Viruses are not cells. Antibiotics do not kill them. Shop-critical viruses include hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV). HBV has a vaccine; that fact belongs with OSHA bloodborne-pathogen training in the next chapter. Human papillomavirus (HPV) causes warts. Herpes simplex causes cold sores. A virus can sit on a contaminated pusher, bit, or razor and enter the next client through broken skin. That is indirect transmission, and it is why N.J.A.C. 13:28-3.1 requires tools applied directly to patrons to be cleaned and sanitized after every use under 13:28-3.2.
Fungi
Fungi include molds, mildews, and yeasts. Named infections you must recognize: tinea capitis (scalp ringworm), tinea pedis (athlete's foot, a pedicure-room classic), tinea barbae (barber's itch), and onychomycosis (nail fungus). Damp towels, undrained pedicure basins, and reused porous files are fungal reservoirs. Mildew in a towel bin is still a fungus problem even when the client does not have a named tinea.
Parasites
Parasites live on or in a host. Pediculosis capitis is a head-louse infestation. Scabies is infestation by the itch mite Sarcoptes scabiei. An active parasitic infestation is a contraindication. You do not disinfect the hair and proceed. You refuse the service, explain, and then process the station so the next client is not the next host.
Direct, indirect, and airborne transmission
NIC Domain 1.A.1 tests the route, not just the organism name.
Direct transmission is person to person: touching an infected lesion, kissing, sexual contact, or a cough that lands on someone. In the chair it looks like working ungloved on a weeping sore, or a stylist with a hangnail nicking a client.
Indirect transmission uses a contaminated object (a fomite): shears, combs, clipper blades, towels, neck strips, nail bits, a pedicure basin, a drawer that was never cleaned. If you rest a used orangewood stick on a folded towel and then drape that towel on the next client, you built an indirect chain. New Jersey's implement rule exists to stop this route.
Airborne and respiratory-droplet transmission occurs when pathogens ride a cough, sneeze, or conversation, or remain suspended. Tuberculosis is the classic airborne bacterial example. That is why N.J.A.C. 13:28-3.2(a)3 requires a chemical disinfectant registered by the Environmental Protection Agency and labeled as being tuberculocidal, or processing in an autoclave registered with the Food and Drug Administration. Tuberculocidal labeling is the chemical performance test New Jersey wrote into shop law. It is not a statement that every client has tuberculosis.
Breaking the chain in a New Jersey shop
A chain of infection needs a reservoir, a pathogen, an exit, a transmission route, an entry, and a susceptible host. You break it by refusing contagious services, by washing hands, by processing multi-use tools under 13:28-3.2, and by discarding what cannot be sanitized. N.J.A.C. 13:28-3.3, as amended in 2009, requires practitioners to wash their hands or use waterless hand-washing agents before and after serving each patron, before and after eating, after handling chemicals, and after using the bathroom. Linens must be laundered and sanitized before each patron contact, or you use disposable toweling (N.J.A.C. 13:28-3.1). None of that is optional salon culture. It is how New Jersey shops are required to interrupt transmission.
A New Jersey cosmetologist-hairstylist finds pus around a client's hairline abrasion after using a comb that had not been processed since the previous client. Which pathogen group is most associated with pus-forming infections on contaminated implements?
A stylist in a licensed New Jersey shop sets used shears on a freshly folded towel, then drapes that towel on the next client. Which transmission route does that sequence create?
Why does N.J.A.C. 13:28-3.2(a)3 require a chemical disinfectant labeled as tuberculocidal, or an FDA-registered autoclave, rather than a product labeled only as effective against HIV and HBV?