Question

Briefly describe an infectious disease and how it affects a human host.

Answer 1

Answer: The discussion is of meningitis which can be bacterial or viral disease.

Meninges are the membranous covering of the brain and the spinal cord. Inflammation of meninges is known as meningitis. The cause of meningitis could be viral or bacterial.

Viral meningitis is more common and less severe than bacterial meningitis. It can be caused by the viruses such as non-polio enteroviruses, herpes virus, mumps virus, measles virus. Close contact with the infected person can cause the disease but normally children below five years of age and immunocompromised individuals are most likely to be affected. The initial symptoms remain same as bacterial meningitis but bacterial meningitis can be more severe because some kind of permanent damage can occur.

No specific treatment is available for viral meningitis as the infection subsides on its own. Protection from the other diseases such as mumps, measles with the vaccines can protect the individual from secondary infection of viral meningitis.

Bacterial meningitis can be caused by the bacteria like Streptococcus pneumoniae, Neisseria meningitidis. Haemophilus influenzae (Hib), group B Streptococci, Listeria monocytogenes Meningitis by Hib is commonly observed in children under five years of age, if the Hib vaccine is not taken. These bacteria cause the upper respiratory tract infection but if it goes into blood, it can cross blood brain barrier and infect the meninges causing meningococcal meningitis. The transmission to the CNS (central nervous system) can occur during surgery, head injury etc.

The most common symptoms of the disease are nausea, vomiting, muscle pain, fever, head ache, joint pain, stiff neck, sluggishness, sore throat.

The treatment has to be immediate or the disease may cause damaged brain function, limb loss, and learning disability or hearing loss.

Transmission of the disease: The disease is highly contagious, the disease spreads through the respiratory secretions of the infected individual, coughing, and sneezing action of the infected individual, which generates the droplets. Listeria monocytogenes can spread through contaminated food. The person most likely to come in contact with the infected person are the medical staff, there is 30% (3 in 10) chance that the health worker will be affected while working with the patient.

Bacterial meningitis can be treated with antibiotics which are usually given intravenously. Meningococcal vaccine is available for Neisseria meningitidis. Hib vaccine for Hib and pneumococcal vaccine are some of the vaccines available to protect against bacterial meningitis caused by these bacteria.

Maintaining hygiene, early detection and proper treatment is necessary to manage bacterial meningitis.