Loa Loa: The “African Eye Worm”

Loa Loa migrating through eye

Loa Loa migrating through eye

Nicknamed “the African eye worm”, Loa loa is one of those tropical parasites that myths and legends are made of.  A medically important parasite from Africa, this is commonly a disease of local people but can effect travelers and adventurers in the endemic areas.

 Basics:

Also known as “African Eye Worm”. Filarial worms migrate through all tissues of the body. Transient swellings and itching are most common symptoms and can take years to appear.

 

Location:

African rainforests and especially Central Africa

 

Transmission/ Incubation:

Transmitted by the bite of an infected Deer Fly (Chrysops species)

Prevention:

Standard flying insect precautions, vector control, 300 mg once per week DEC (diethylcarbamazine) for high risk persons

 

Diagnosis:

Demonstration of microfilariae in daytime drawn blood smear

 

Treatment:

Diethylcarbamazine (DEC) 5-10 mg/kg three times per day for 3-4 weeks generally kills larvae and eliminates adult worms. Treat possible histamine/allergic based reactions with antihistamines/steroids. Albendazole and ivermectin may have a slower kill of larvae, causing a less severe treatment reaction.

 

Chrysops fly

Chrysops fly

This parasite is very similiar to the other nematodes including W. bancrofti.  however, this worm likes to move through tissues, without setting up a real permanent residency.  Soem trouble with this infection can occur when treatment begins.  Use of medications often used to treat other parasitic infections, found in the same geographic area, can cause bad reactions.  Caution should be used with ivermectine (treatment for onchocerciasis) as encephalitis/brain swelling can occur.  Common treatment reactions with DEC can involve histamine and typically respond well to antihistamines and/or steroids.

 

distribution of common parasitic infection

distribution of common parasitic infection

 

 

 

 

 

 

Brazil Yellow Fever Alert

Brazil will release an official Yellow Fever Alert, later today. This is in response to the second death from Yellow Fever, in Brasilia. The country is also reporting to step up their YF vaccine program, as well.
ProMed Mail

Brazil was recently in the travel medicine news with a few deaths from yellow fever vaccines, in Peru. The deaths were associated with a Brazilian pharmaceutical company that produces the vaccine. More on a previous post

Adventure Doc

Tropical Disease burden shared by Travelers

A recent news article in Medical News Today discussed the risk travelers have and burdens they could suffer from the “negelected tropical diseases” such as filariasis, schistosomes, river blindness and many others.

The GeoSentinel is a global health warning system that is also mentioned in the article. Maintained as a joint venture by the CDC (center for disease control) and ISTM (international society of travel medicine), this is a way for public health practitioners to exchange information on potential outbreaks.

The article sites another publication with this submission:
Filariasis in Travelers Presenting to the GeoSentinel Surveillance Network
Ettie M. Lipner, Melissa A. Law, Elizabeth Barnett, Jay S. Keystone, Frank von Sonnenburg, Louis Loutan, D. Rebecca Prevots, Amy D. Klion, Thomas B. Nutman, for the GeoSentinel Surveillance Network.

This article details filarial infections and rates/risks determined by the GeoSentinel system.

Adventure Doc

Public Library of Science Negelected Tropical Diseases

A resource that I am finding very interesting reading is from the Public Library of Science on-line Journal of Negelected Tropical Diseases. The PLoS series of journals are open source and peer reviewed. They are also available free, on-line.

I thought a few other people might enjoy some of their articles.

Adventure Doc

CDC Removes Malaria Precautions in Bahamas

A new update from the CDC has removed cautions for malaria in the Bahamas. The specific area in the Bahams include Great Exuma. Travelers are cautioned to continue to take insect bite precautions, but anit-malarial medications are no longer required.

The original advice to use anti-malarial medication stemmed from 2 cases of malaria reported in August, 2007. Prior to that, there were several confirmed cases in 2006, as well. The Bahamas are not an area known for malaria transmission.

You can follow the battle against mosquitoes in the Caribbean over at a very informative site called: http://woodshedenvironment.wordpress.com/

Any travelers going to the Bahamas shoud consult the CDC Travel Notices Page for updates on the current sitituation and advice.

Adventure Doc Malaria Page

Tropical Medicine Super-Site

I came along an amazing website for tropical medicine.  The Tropical Medicine Central Resource associated with the Uniformed Services University of Health Sciences has a very detailed registry of tropical medicine diseases that includes life cycle basics, geography, diagnostics and images, epidemiology and clincal descriptions.

 The Website is the online version of a textbook titled: The Imaging of Tropical Diseases, with Epidemiological, Pathological and Clincal Corrilation.

This site should be bookmarked for reference by anybody who studies tropical medicine.

 The Introduction of the Book is very cool and sums up the author’s goals:

This website contains the 1700 page, 2 volume textbook “The Imaging of Tropical Diseases, with Epidemiological, Pathological and Clinical Corrilation”. This project is presented with the gracious permission of the authors Philip E.S. Palmer MD, FRCR, FRCP, and Maurice M. Reeder MD, FACR, and of the publisher Springer-Verlag, Berlin, Heidelberg, New York; who holds the copyright to the book. All physcians and radiologist in the U.S. Military services, as well as their counterparts woh labor in developing countries of the tropical or so-called Third World and who cannot afford the cost of expensive textbooks, are welcome to take advantage of this remakable collection of images and background information gathered over a 40 year period by the authors from all regions of the world. It is the hopes of the authors and publicher that the provisions of this treatise freely to those who see and treat patients with these myriad tropical maladies will result in earlier and more accurate diagnosis and subsequent diminution in their morbidity and mortality.

The authors wish to thank Mr. Robert Reeder, Mr. Micheal Usera and Dr. James Smirnitopolis MD, for their considerable efforts and computer expertise in making this website possible.

Here’s that link to this amazing resource…

http://tmcr.usuhs.mil/

A big thanks to the people who publish, write and produce that site!

Adventure Doc

Pet Related Infections Article

A very good article on Pet Related Infections can be found at the American Family Physician website (Am Fam Physician 2007;76:1314-22). The article, written by an MD and two vets, covers zoonosis very well. Most of the illness are not specific to household pets and have application to wild animals and travelers, as well.  This is a very informative and well written piece that deserves to be read by any person who treats people in contact with animals.

The authors are: PETER M. RABINOWITZ, MD, MPH, ZIMRA GORDON, DVM, MPH and LYNDA ODOFIN, DVM, MSPH.

Adventure Doc

Chinese Surgery for Elephantiasis

The Taipei Times has a story about a woman from Peru undergoing an operation to treat her elephantiasis. This is of interest to me, because the standard thoughts on treatment of this disease do not include surgery. In fact, surgery has been shown to worsen the symptoms of blocked lymphatic channels.

The 45 year old woman, from Peru, will undergo an operation on her right leg, which now weighs 50 kg. The surgeon, Chen Hung-chi, specializes in plastic surgery and specifically elephantiasis.

This disease is caused by filaria (microscopic worms) that are acquired form the bite of an infected mosquito. The worms grow into adults and migrate to the lymphatic channels of the legs, blocking them. The results are massive swelling and infections of the legs. Treatment has traditionally been antibiotics to kill the worms. The swollen leg, unfortunately, never goes back to “normal” size. Surgery has also been contraversial because it scars the already damaged lymphatic channels, often making the blockages worse.

The Parasite that causes this, most commonly, is Wucheria Bancrofti. The group of parasite W. Bancrofti belongs with are called Helminthes and they cause some pretty interesting diseases, too.

Tropical Medicine Vignette

Here is the latest tropical medicine vignette from the McGill-CanTropMed listserv. Each month they send out a new picture and brief information on a tropical medicine disease. The answer can be found by clicking a link at the bottom of the page. Thanks to the McGill University Ceter for Tropical Diseases for this service and J Dick MacLean MD, FRCPC, MRCP(UK) DCMT(Lond) who is the Director/Professor.

Here is this month’s link: Tropical Med Vignette. Also, here is the link for the archives of previous questions.

Good luck!

Adventure Doc Tropical Medicine Page

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