Coccidioides imitis is a soil fungus that requires alkaline soil to grow. It is found in arid regions from California to Texas and in areas of Central and South America. It causes “Valley Fever”, which can mimic the flu, but is not contagious from person to person.
Coccidioides infection begins when animals or people inhale its arthroconidia. These are the soil form of the organism, usually found in the top four inches of desert soil.
Tourists passing through the Southwestern US may inhale large numbers of infectious arthroconidia.
When they reach the lungs, they grow and form spherules, the next stage in the Coccidioides life cycle.
Our immune response to the fungal infection can result in fatigue, fever, cough, chest pain, headaches, rash, nightsweats, muscle pain, joint aches, weight loss and poor appetite.
These are the symptoms of Valley Fever.
Valley Fever spherules in our tissues soon become surrounded by layers of white blood cells. Since the white blood cells can’t kill the fungus, they try to wall it off.
Each granuloma is like an onion, with multiple layers of immune response cells surrounding its core of Coccidioides spherules.
Pathologists can use a microscope to see these granulomata and spherules in a tissue biopsy, allowing them to diagnose the fungal infection. Serology tests for Coccidioides are available, too, but may be unreliable in certain patients.
Doctors may have problems diagnosing Coccidioides infection, especially in areas where the fungus does not reside.
Even with a relatively strong immune system, tissue destruction and lung cavity formation can occur from Coccidioides infection.
Theis patient has a left lung cavity (hole eaten in lung tissue) from the fungal infection.
Radiologists can turn up the contrast on CT scan images to better see the extent of Coccidioides lung disease.
(Compare upper to lower image)
The fungal lung infection can affect the adjacent pleural membranes, pericardium and even the heart itself.
Bacteria from the mouth can find their way into a Cocci cavity, forming an abscess. This can cause high fevers, chest pain and malaise. Coccidioides infection can cause lung scarring, shrinking the involved lung. This patient’s diaphragm is pulled up into a “tent” or peak from scarring near the cavity.
Pus that breaks out of a lung cavity into the adjacent pleural space forms an empyema.
Empyemas require a thoracostomy tube for drainage.
If the empyema fluid is too thick to be removed by tube, surgical drainage is required for resolution.
Video Assisted Thoracoscopy or open thoracic surgery are used to remove the pleural “peel” (the “peel” forms from severe inflammation and pus remaining in the pleural space for weeks or months).
Someone with a weak immune system may die from disseminated infection (when Coccidioides spreads out of the lungs to involve the brain, bones, skin or other sites).
Patients with emphysema, diabetes, cancer chemotherapy, ongoing pregnancy or other immunosuppressive problems are more prone to severe disease with Coccidioides fungus.
Persons of Filipino, Polynesian and African ancestry can also suffer severe problems with the infection. Their immune systems are less effective in controlling the fungus.
Patients with disseminated disease are unable to contain the fungus. Involvement of brain, bones, abdominal viscera, muscles and soft tissues can be life-threatening. Most cases of disseminated Coccidioides are fatal without treatment.
Coccidioides fungus can activate the immune system, causing rashes of all sorts.
Joint pain, fatigue, red eyes, ulcers in the mouth and swelling of the lips and tongue can all be present with the rash.
Erythema multiforme is a flat or somewhat raised rash of doughnut or ring-shaped lesions that have a red or purple color. The rings may be clearly evident as in the photo above, or less obvious, as seen below.
The rash, joint aches, lip and tongue swelling, fatigue and red eyes usually resolve promptly on treatment for Coccidioides infection. These rashes and other symptoms occur from immune system activation by the fungus.
Erythema nodosum is a different sort of skin inflammation than erythema multiforme. It consists of large tender nodules beneath the skin. These usually occur on the front of the legs, but they can appear anywhere on the body in patients with Coccidoides infection. No Coccidioides fungus is found in these lesions; they are due to immune system stimulation by the infection.
Coccidioides therapy may include the different classes of anti-fungal drugs shown above.
Azoles are commonly used in patients able to take oral therapy (fluconazole, itraconazole, voriconazole, posaconazole).
Echinocandins are less easy to use outside of a hospital, since they are given intravenously.
Amphotericin B formulations are also intravenous, and are usually given to more seriously ill patients.
For more information about Valley Fever, visit
Valley Fever Center for Excellence website.
Immigrants and infectious diseases are a major concern in many areas of the world. Here is a list of the most common diseases carried by immigrants.
Large numbers of people are on the move across the globe, and infectious diseases are moving with them. Which diseases are they? How can we stop them? What sort of screening should be in place for immigrants?
Here is a list of the most common infectious diseases associated with immigration:
Injected by Anopheles mosquitoes, these protozoa infect our liver and red blood cells, destroying them. Periodic fevers, chills and severe body aches result, along with anemia.
New rapid tests can diagnose the malaria quickly, so that individuals can be treated and avoid infecting mosquitoes in the new areas that they enter.
Typhoid fever results when Salmonella bacteria enter the bloodstream from the colon.
Salmonella bacteria reside in water that is been contaminated by feces from humans or animals, and in poorly cooked eggs and chickens. Human chronic carriers may shed huge numbers of the bacteria in their stool, contaminating rivers, wells or other water supplies when they defecate in them or touch food with unwashed hands.
One in 10 people with cholera will have severe disease characterized by profuse watery diarrhea, vomiting, and leg cramps. In these people, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours. As with Salmonella, water and hands contaminated by diarrhea can cause rapid spread of the disease.
Hepatitis A and E are present in the stool of individuals soon after they become infected. Large numbers of new cases can occur in places where people are unable to wash their hands and touch food eaten by others.
Hepatitis B and C are present in blood and semen of infected persons. These are spread by needle-sharing, sex and blood transfusions.
In places where violence has occurred, open wounds can be a source for transmission of Hepatitis C, which is 100 times more contagious than HIV. Virus in wound fluids can enter through a small break in a caregiver’s skin to infect them.
Transmission through sex by persons who do not even know that they are infected is common in many third world countries (and still occurs in more advanced countries). Unborn children can also be infected, and testing of all pregnant women is advised.
The tests for these organisms are very sensitive, and are important in diagnosing the infections early (before HIV causes severe immune system damage, and before syphilis enters the brain or causes harm to the fetus).
Treatment for both is now available, but may be expensive in the case of HIV.
Highly contagious if active, TB is frightening. Antibiotic resistant strains are now common in many parts of the world. Testing is not always reliable, and problems are already advanced if the person has an abnormal chest x-ray.
Isolation and TB therapy with several antibiotics at once are necessary for control.
Hopefully, countries receiving immigrants and the countries of their origin will be able to afford to treat ill individuals adequately. Medications for HIV and TB in particular can be very expensive and in short supply.
Tropical diseases like Leprosy, Sleeping Sickness (trypanosomiasis), Chagas disease, Filariasis, and Schistosomiasis are not easily transmitted to others, but may cause health problems later for international travelers who do not receive medical attention.
Immigrant/refugee screening tests:
Acute hepatitis panel
Sputum ×3 if chest x-ray abnormal
Over the and parasite exam on stool
Albendazole/ivermectin empiric therapy
Vision and hearing assessments for children
Airport screening for Ebola-infected individuals goes into effect today.
In light of cries to do something from the terrified public, many governments are instituting such measures, ineffective though they may be.
The incubation period of 2-21 days for Ebola and other viral hemorrhagic fevers makes it difficult to detect them early. Infected individuals may be long past the screeners when they become ill.
Contact with sick individuals will also not be reported, in some cases.
Our best protection is to be alert when dealing with sick persons; asking them appropriate questions about where they have been and what they have been doing prior to their illness. Gowns, gloves, mask and eye shields should be donned for any patient from an endemic area who has bleeding, diarrhea or vomiting.
Influenza vaccination of the public and health care workers should be encouraged beginning immediately. Since hemorrhagic fever patients have a flu-like illness, our ability to detect them will be enhanced if fewer influenza patients are around.
Ravenous hordes of mosquitos devoured my Brazilian guides in the Pantanal this June.
I didn’t get a single bite, or come away with any mosquito-borne diseases.
The mosquitos there carry life-threatening diseases including malaria, yellow fever, dengue and other arboviruses.
Here is what I used to prevent bites:
Sawyer Products Ultra 30 Liposomal DEET
Insect repellent for skin application
Very little odor, long lasting even when wet or sweating.
Easy to re-apply while on river / in forest from handy 3 oz bottle.
For clothing and bed mosquito net (sleeping under a mosquito net at night is a good idea in such places)
This treatment was done in garage at home, before leaving the USA.
Essentria General Household Insect Control Spray
Knockdown spray for crawling and flying insects
Octopamine blocker – prevents insect nerves from working without causing human nerve problems
Wondering what to wear for Ebola protection?
You can pack like the experts!
Some Ebola strains have been able to cause infections via an airborne route (Ebola Reston, as in “Hot Zone”), but the presently problematic strain has not shown such spread at this time.