In: Biology
1.Discuss Rockey Mountain Spotted Fever. What is a Rickettsial organism and how does it differ from other groups pf bacteria. Discuss the life cycle of the disease including the vector and the host, the symptoms of the disease and transmission. How important is the disease here in Dallas and how can you prevent being infected even if you were bitten by an infected tick? What is the treatment for the disease?
2.Discuss syphilis, include the morphology of the organism, its means of transmission, symptoms of the different stages of the disease, and the treatment presently used. What impact has this disease had on world populations. Do you think there is a possibility of eradicating this syphilis from the world population? When and how?
1.
Rocky Mountain spotted fever is a severe illness caused by tiny bacteria called Rickettsia rickettsii, which are transmitted through the bite of an infected tick. In the eastern United States and in California, the infected tick is usually Dermacentor variabilis, the American dog tick. In most of the western United States, the tick is more likely to be Dermacentor andersoni, the Rocky Mountain wood tick. Humans typically become infected in the spring and early summer.
Once someone is bitten by an infected tick, Rocky Mountain spotted fever bacteria can spread throughout the bloodstream and lymphatic system. The tick must remain attached and be actively feeding to transmit the bacteria. Not everybody who is bitten by an infected tick develops Rocky Mountain spotted fever. It is not clear why some people get the disease and others do not.
Once in the body, the bacteria attack and severely damage the linings of blood vessels. The injured vessels leak a watery fluid, which causes swelling. The blood vessels also can lose blood, which causes potentially life-threatening hemorrhages (serious bleeding). As damaged blood vessels continue to leak, blood pressure can decrease. If this happens, blood flow to the kidneys can decrease, causing kidney damage and, possibly, kidney failure. Rocky Mountain spotted fever bacteria also may attack the brain directly, causing symptoms of encephalitis (brain infection) or meningoencephalitis (infection of the brain and its surrounding membranes). Rocky Mountain spotted fever also can cause jaundice (yellowing of the skin and eyes) as a result of liver injury. In the lungs, Rocky Mountain spotted fever can lead to an accumulation of fluid in the lungs (pulmonary edema) and severe breathing difficulties.
The U.S. Centers for Disease Control and Prevention (CDC) up to 4000 cases of Rocky Mountain spotted fever or related infections in the United States each year. Children aged 5 to 9 are more likely to be infected than any other age group.
Symptoms
Typically, symptoms begin 2 to 14 days after a tick bite, with an average of 1 week. During the first 3 days of symptoms, an infected person usually has a fever of more than 102 degrees Fahrenheit and a severe headache. Muscle aches, nausea and vomiting are common. Between the 3rd and 5th day of fever, most people develop a rash, which usually begins on the wrists and ankles, then spreads to the arms, legs and trunk. In about two-thirds of patients, the rash also involves the palms of the hands and the soles of the feet. On day 6 or later, the areas of rash may show tiny broken blood vessels and small hemorrhages under the skin.
Other symptoms of Rocky Mountain spotted fever include:
Diagnosis
The classic features that may lead your doctor to suspect Rocky Mountain spotted fever are high fever, rash, headache, and a history of tick exposure, such as walking in a tick-infested area, within 14 days of developing the symptoms of Rocky Mountain spotted fever. Only about 60% of patients recall being bitten by a tick.
The early symptoms of Rocky Mountain spotted fever are not specific, and diagnostic tests often are negative early in the disease. Therefore, if your doctor suspects that you have Rocky Mountain spotted fever, he or she generally will begin treatment immediately, even if your blood tests are negative. Early treatment is essential to help you avoid severe complications. Your doctor also may remove a small piece of skin from the area of the rash so it can be examined in a laboratory. This procedure is called a biopsy. The biopsy sample can be tested in the laboratory with chemicals to confirm the presence of Rocky Mountain spotted fever bacteria. Blood tests can confirm the diagnosis, but only two to three weeks after the onset of infection. There are no specific abnormalities on blood tests that indicate an active infection early on.
Expected Duration
Symptoms of Rocky Mountain spotted fever begin 2 to 14 days after a bite by an infected tick. Most cases of Rocky Mountain spotted fever respond to appropriate antibiotic treatment within a week. Once symptoms develop, a person can die within 2 weeks without proper treatment.
Prevention
Because there is no vaccine against Rocky Mountain spotted fever, the most effective way to prevent the illness is to avoid walking in wooded areas or fields where ticks are found. If you must walk in tick-infested areas, follow these precautions:
Treatment
Rocky Mountain spotted fever is treated with one of the tetracycline drugs, usually doxycycline (sold as a generic), in adults and children over age 9. In general, tetracyclines should not be prescribed for pregnant women and children under the age of 9 because these antibiotics can permanently stain the teeth. However, doxycycline is the best available antibiotic to treat this potentially life threatening infection and is preferred if Rocky Mountain spotted fever is the likely diagnosis, despite the teeth staining. Chloramphenicol (Chloromycetin) is another antibiotic that attacks the bacteria, but it appears to be less effective than doxycycline and is only recommended when doxycycline cannot be given due to allergy or other reaction.
Most people are cured after taking the antibiotics for five to seven days. Patients may need to be hospitalized if there is severe lung damage, kidney failure, significant bleeding or severe brain involvement. In cases of respiratory failure, mechanical ventilation (treatment with a machine that breathes for the patient) may be necessary. Patients with kidney failure may require dialysis. Those with severe bleeding may need blood transfusions.
2.
Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria known as Treponema pallidum. In 2016, more than 88,000 cases of syphilisTrusted Source were reported in the United States, according to the Centers for Disease Control and Prevention. The rate of women with syphilis has been declining in the United States, but the rate among men, particularly men who have sex with men, has been rising.
The first sign of syphilis is a small, painless sore. It can appear on the sexual organs, rectum, or inside the mouth. This sore is called a chancre. People often fail to notice it right away.
Syphilis can be challenging to diagnose. Someone can have it without showing any symptoms for years. However, the earlier syphilis is discovered, the better. Syphilis that remains untreated for a long time can cause major damage to important organs, like the heart and brain.
Syphilis is only spread through direct contact with syphilitic chancres. It can’t be transmitted by sharing a toilet with another person, wearing another person’s clothing, or using another person’s eating utensils.
Stages of syphilis infection
The four stages of syphilis are:
Syphilis is most infectious in the first two stages.
When syphilis is in the hidden, or latent, stage, the disease remains active but often with no symptoms. Tertiary syphilis is the most destructive to health.
Primary syphilis
The primary stage of syphilis occurs about three to four weeks after a person contracts the bacteria. It begins with a small, round sore called a chancre. A chancre is painless, but it’s highly infectious. This sore may appear wherever the bacteria entered the body, such as on or inside the mouth, genitals, or rectum.
On average, the sore shows up around three weeks after infection, but it can take between 10 and 90 days to appear. The sore remains for anywhere between two to six weeks.
Syphilis is transmitted by direct contact with a sore. This usually occurs during sexual activity, including oral sex.
Secondary syphilis
Skin rashes and a sore throat may develop during the second stage of syphilis. The rash won’t itch and is usually found on the palms and soles, but it may occur anywhere on the body. Some people don’t notice the rash before it goes away.
Other symptoms of secondary syphilis may include:
These symptoms will go away whether or not treatment is received. However, without treatment, a person still has syphilis.
Secondary syphilis is often mistaken for another condition.
Latent syphilis
The third stage of syphilis is the latent, or hidden, stage. The primary and secondary symptoms disappear, and there won’t be any noticeable symptoms at this stage. However, the bacteria remain in the body. This stage could last for years before progressing to tertiary syphilis.
Tertiary syphilis
The last stage of infection is tertiary syphilis. According to the Mayo Clinic, approximately 15 to 30 percent of people who don’t receive treatment for syphilis will enter this stage. Tertiary syphilis can occur years or decades after the initial infection. Tertiary syphilis can be life-threatening. Some other potential outcomes of tertiary syphilis include:
Picture of syphilis
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During the secondary stage of syphilis, people develop red or reddish-brown bumps or patches, and they are very infectious at this point.
How is syphilis diagnosed?
If you think you might have syphilis, go to your doctor as soon as possible. They’ll take a blood sample to run tests, and they’ll also conduct a thorough physical examination. If a sore is present, your doctor may take a sample from the sore to determine if the syphilis bacteria are present.
If your doctor suspects that you’re having nervous system problems because of tertiary syphilis, you may need a lumbar puncture, or spinal tap. During this procedure, spinal fluid is collected so that your doctor can test for syphilis bacteria.
If you’re pregnant, your doctor might screen you for syphilis because the bacteria can be in your body without you knowing it. This is to prevent the fetus from being infected with congenital syphilis. Congenital syphilis can cause severe damage in a newborn and can even be fatal.
Treating and curing syphilis
Primary and secondary syphilis are easy to treat with a penicillin injection. Penicillin is one of the most widely used antibiotics and is usually effective in treating syphilis. People who are allergic to penicillin will likely be treated with a different antibiotic, such as:
If you have neurosyphilis, you’ll get daily doses of penicillin intravenously. This will often require a brief hospital stay. Unfortunately, the damage caused by late syphilis can’t be reversed. The bacteria can be killed, but treatment will most likely focus on easing pain and discomfort.
During treatment, make sure to avoid sexual contact until all sores on your body are healed and your doctor tells you it’s safe to resume sex. If you’re sexually active, your partner should be treated as well. Don’t resume sexual activity until you and your partner have completed treatment.
How to prevent syphilis
The best way to prevent syphilis is to practice safe sex. Use condoms during any type of sexual contact. In addition, it may be helpful to:
Syphilis can also be transmitted through shared needles. Avoid sharing needles if using injected drugs.