Viruses and Other Microorganisms - NCLEX-PN

Rhinovirus, a type of picornavirus, is implicated in up to 50-80% of cases of the common cold. Other less common causes include human coronavirus (15% of cases), influenza (10%), and adenovirus (5%).

The majority of infectious vomiting and diarrhea in infants and young children is viral in origin, with the most commonly implicated virus being rotavirus. Norovirus is another common cause of viral gastroenteritis in individuals of all ages, though it is not as common in young children as rotavirus.

In most children and adults, Zika virus causes a mild fever characterized by myalgia, fatigue, and headache. The population most at risk for serious complications from the disease is unborn fetuses. Exposure to Zika virus before birth has been associated with microcephaly, a frequently fatal disorder of abnormal skull and brain development.

Zika virus is primarily transmitted via mosquito bite. However, it can also be transmitted by sexual contact and it can cross the placenta, allowing an infected mother to pass the virus to an unborn child.

Koplik's spots are oral lesions seen early-on in infection with the measles virus. These spots are only present in a minority of cases, though. Other common symptoms of measles include high fever (often over 104 degrees fahrenheit), cough, runny nose, and a maculopapular rash which begins at the hair line and spreads down to the trunk and extremities.

The most noticeable symptom in mumps infection is enlargement of the parotid glands, while Epstein Barr infection can result in fatigue, lymphadenopathy, and hepatosplenomegaly. Scarlet fever is not a viral infection, but rather is caused by the bacteria streptococcus pyogenes.

The measles virus is one of the most highly contagious of all childhood exanthems. It is spread primarily by respiratory droplets, or by touching a surface that has been in contact with an infected individual's saliva or mucus. It is not spread in feces, nor is it blood or vector borne.

Measles, while generally only a moderately severe disease, is fatal in one out of every 500 children who contract the virus.

Genital herpes is most frequently associated with herpes simplex virus 2 (HSV2), while herpes simplex virus 1 (HSV1) has been associated more often with oral herpes (cold sores). However, new evidence suggests that both viruses can live in either location: HSV1 can spread to the genitals and cause genital herpes, while HSV2 can be spread to the oral mucosa to cause cold sores.

An infection of the finger, toe, or cuticle with the herpes simplex virus is known as a herpetic whitlow. This infection causes painful swelling and erythema at the site of contact and is often caused by the finger coming into contact with a cold sore (oral herpes simplex lesion). It is more common in individuals who are frequently in contact with oral mucosa, such as dentists and dental hygienist, nurses, and in individuals who bite their nails or suck their fingers or thumb.

The most common cause of infectious hearing loss in neonates is cytomegalovirus (CMV), also known as human herpes virus 5. While this disease rarely causes symptoms in adults, it can cause significant harm to a fetus. One of the primary fetal consequences of CMV infection in pregnancy is hearing loss. Other issues can include vision loss, developmental delays, and seizures.

All of the other infections listed can have significant impacts on the health of a fetus or neonate, including pre-term birth, spontaneous abortion, and vision loss, though none are currently associated with risk of hearing loss.

In adult populations, cytomegalovirus poses the greatest risk to immunocompromised individuals, such as people on immunosuppressive drugs or in HIV patients who have developed AIDS. In pregnant people, CMV generally does not pose a risk to the mother, but rather to the fetus. Athletes and teens that are not immunocompromised often will have mild or unnoticeable symptoms when infected with CMV.

Human papillomavirus, herpes simplex virus, and hepatitis B virus are a sexually-transmitted viruses with double-stranded DNA genomes. While herpes simplex virus has a relatively large genome, the genome of both human papillomavirus and hepatitis B virus are both quite small.

Orchitis due to mumps has decreased significantly due to vaccination, but it is still a significant risk in unvaccinated individuals. Mumps-related orchitis can result in testicular failure later in life. None of the other microbial infections listed have an association with orchitis.

Individuals with hepatitis C have a much higher incidence of development of type II diabetes. This is thought to be due to increased levels of tumor necrosis factor (TNF)-alpha, which leads to insulin resistance. Gaucher's disease is a hereditary disorder of glucosylceramide accumulation that can affect the liver but is not caused by hepatitis C virus. Wasting syndrome is a general term for individuals who experience unintentional weight loss due to a disease such as cancer. Fabry disease is a rare liposomal storage disorder unrelated to any viral infection.

This question requires the student to distinguish between the rashes that are common in children; specifically those that may be present due to fear of immunizations. Measles begins with Koplik's spot in the mouth. Then the rash first appears on the forehead. Rubella first appears on the trunk, then spreads throughout the body. Chicken pox manifests as fluid-filled vesicles. Smallpox appears as blister-like lesions and this disease has been eradicated for a few decades.

All forms of warts are caused by the virus HPV, or human papillomavirus. In addition, HPV is the cause of a variety of dysplasias, including cervical dysplasia, vulvar dysplasia, and oropharyngeal cancer. None of the other viruses listed are associated with warts of any kind.

While all of the strains of HPV may cause condylomata acuminata, 90% of all cases of genital warts are caused by just two strains: 6 and 11.

Human papillomavirus has been associated with several forms of cancer, including cancers of the cervix, vulva, anus, and oropharynx. It is also associated with penile and vaginal dysplasias.

While HPV strains 31 and 33 have been associated with genital malignancies, more than 70% of cervical dysplasia is associated with HPV strains 16 and 18. Strains 6 and 11 are associated with genital warts, while 2 and 7 are associated with common warts.