Human System Infectious Diseases

¶ … anatomy and physiology of the Nervous System

The nervous system is a "network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment." ("Nervous System 2000) There are two segments of the nervous system which include the peripheral and central systems. ("Nervous System 2000)

The peripheral nervous system consists of spinal, cranial, and autonomic nerves, and their branches. ("Nervous System" 2000)

The central nervous system consists of the spinal chord and brain.

The brain might be compared to a computer and its memory banks, the spinal cord to the conducting cable for the computer's input and output, and the nerves to a circuit supplying input information to the cable and transmitting the output to muscles and organs. The nervous system is built up of nerve cells, called neurons, which are supported and protected by other cells. Of the 200 billion or so neurons making up the human nervous system, approximately half are found in the brain. From the cell body of a typical neuron extend one or more outgrowths (dendrites), threadlike structures that divide and subdivide into ever smaller branches. Another, usually longer structure called the axon also stretches from the cell body. It sometimes branches along its length but always branches at its microscopic tip. When the cell body of a neuron is chemically stimulated, it generates an impulse that passes from the axon of one neuron to the dendrite of another; the junction between axon and dendrite is called a synapse. Such impulses carry information throughout the nervous system. Electrical impulses may pass directly from axon to axon, from axon to dendrite, or from dendrite to dendrite." ("Nervous System" 2000)

Bacterial Meningitis

Bacterial Meningitis is a serious disease that can have grave consequences if left untreated. Though many people survive after being properly treated, the long lasting impacts of the disease on the nervous system can be devastating. An article in the journal Developmental Neuropsychology, explains the causes of bacterial meningitis. The author explains,

Meningeal bacterial infection may be caused by a number of organisms, of which Neisseria meningitidis, Streptococcus pneumoniae, and Hemophilus influenzae account for the vast majority of diagnosed cases. During the first decade of life, S. pneumoniae usually ranks third in frequency; it is second to N. meningitidis in older childhood and young adulthood, but in older adults the pneumococcus is the most common pathogen (Geiseler, Nelson, Levin, Reddi, & Moses, 1980). Pneumococcal meningitis was usually fatal before the introduction of antibiotics. Today it is survived by about 80% of the patients. An important question is the quality of life of the survivors. (Garret 1992)

Indeed, the quality of life for survivals can be greatly affected by the impact that the bacteria has on the body. In may cases the disease leads to paralysis and decreases in cognitive abilities. Many who recover from the disease are confined to wheel chairs and children affected by the disease may have difficulty learning and developmental delays.

Temperature, Cultivation and Identification

The Meningitis Manual, published by the Centers for Disease Control discusses the methods of cultivation and identification of the bacteria. The manual explains,

As soon as the CSF has been collected, it should be transported to the microbiology laboratory, where it should be examined as soon as possible (within one hour from the time of collection).Do not expose the CSF to sunlight or extreme heat or cold. If N. meningitidis is suspected to be the cause of the illness, and a delay of several hours in processing specimens is anticipated, incubating the CSF (with screw-caps loosened) at 35 •C in a 5% CO2 atmosphere (or candle-jar) may improve bacterial survival... Once the CSF has arrived at the microbiology laboratory, centrifuge it for 20 minutes at 2000 rpm. Draw off the supernatant with a Pasteur pipette. When antigen detection by latex agglutination is planned, save the supernatant. Sediment must be either vigorously vortexed or well mixed. Use one or two drops of sediment to prepare the Gram stain and use 1 drop to streak the primary culture media... N. meningitidis may occur intra- or extra-cellularly in the polymorphonuclearleukocytes and will appear as Gram-negative, coffee-bean-shaped diplococci. S. pneumoniae are lanceolate, Gram-positive diplococci sometimes occurring in short chains. H. influenzae are small, pleomorphic Gram-negative rods or coccobacilli with random arrangements. Other manuals should be consulted for Gram stain reactions of other bacteria. (Meningitis Manual 1998)

Symptoms, Treatment, Transmission, Prevention and Epidemiology

According to the Centers for Disease control the symptoms of meningitis in individuals over 2 years of age include; a stiff neck, fever. headache, nausea, confusion and vomiting. (Meningococcal Disease 2002) For individuals under the age of two symptoms may include poor eating, vomiting and irritability. (Meningococcal Disease 2002) As the disease progresses some people may have seizures. (Meningococcal Disease 2002

The disease is treated through the use of several antibiotics and medicines including; penicillin, sulfamethiazole, sulfadiazine, and streptomycin. (Garret 1992) The types of antibiotics that are used are dependent upon the type of bacterial meningitis that the individual has contracted. Overall antibiotics are very effective in treating the disease. (Meningococcal Disease 2002

The Centers for Disease Control explains that bacterial meningitis can be spread "through the exchange of respiratory and throat secretions (i.e., coughing, kissing). Fortunately, none of the bacteria that cause meningitis are as contagious as things like the common cold or the flu, and they are not spread by casual contact or by simply breathing the air where a person with meningitis has been." (Meningococcal Disease 2002) great deal of people contract the disease through prolonged exposure to someone carrying the bacteria. (Meningococcal Disease 2002)

There are preventative steps that can be taken to avoid meningitis include maintaining sanitary condition, getting vaccinated and steering clear of people that are coughing or sneezing.

The Centers for Disease Control reports that world wide there were 0.5-5/100,000 endemic diseases. (Meningococcal Disease 2002)

The CDC also reports that there were "213,658 cases with 21,830 deaths reported in West African countries. Up to 2% in epidemics in Africa." (Meningococcal Disease 2002) The CDC reports that the meningitis epidemic will continue in Africa. They also estimate that new serogroup in the United States and Africa will contribute to the increased frequency of outbreaks. (Meningococcal Disease 2002)

These outbreaks also "changes distribution of serogroups responsible for endemic disease." (Meningococcal Disease 2002)