The design projects that we will be working on in the seminar are all part of a program to improve health care in developing countries. In particular we will look at projects related to the following topics:
development of a tuberculosis testing stations for remote clinics
development of a syphilis testing station for remote clinics
development of a water treatment system
development of a computerized diagnostic tool for sexually transmitted diseases
Many of the projects that will be used in remote health care clinics may be subject to unique constraints: sources of electricity are unreliable, technicians have limited training, and trained maintenance personnel and equipment are lacking.
The following describes each of the programs listed above and lists the design projects associated with them. The list of projects that the students worked on this semester can be found at the end of this page.
Development of a Tuberculosis Testing Stations for Remote Clinics
Among infectious diseases, tuberculosis is the leading killer of adults in the world today, and poses a serious challenge to international public health work. Fully one third of the world's entire population is now infected with the TB bacillus. In the next decade it is estimated that 300 million more people will become infected, that 90 million people will develop the disease, and 30 million people will die from it. TB is especially devastating in developing countries, where it accounts for more than a quarter of all preventable adult deaths. Because TB is very infectious, it is important for the diagnosis and treatment of the disease to be wide-spread in order for it to be effective. Research is being done to develop a quick dip-stick test, but until that project is complete, screening for the disease is done by a sputum smear test.
The screening process for tuberculosis is time-consuming and not widely available. The test is done by taking a sputum sample, staining it and looking at it under a microscope. There are two ways in which this can be done. In the first method, a gob of sputum is placed on a slide and stained. Because the gob is thick and the surface uneven, it is necessary to re-focus the microscope often in order to properly view the sample. It takes at least 15 minutes to do so and it is difficult to get an accurate reading. In the other method, the sputum sample is spun down in a centrifuge and the fraction which contains the most bacteria is separated out. This is placed on a warmed slide, causing it to spread out in a thin layer which is then stained and viewed through the microscope. This is the preferred method, as a more accurate screening can be done, since the bacteria are more concentrated and the sample is easier to view.
The following equipment is required:
(TB1) A device for separating the different fractions of the sputum samples.
(TB2) A device for warming microscope slides.
(TB3) A device for viewing the samples.
In addition to screening for TB, another problem is treating the disease. The patient must take 10 - 12 tablets daily for an extended period (about 6 months). Patients often do not follow through with the entire course of treatment. Failure to complete the treatment leads to reinfection by drug- resistant (MDR) TB (which has a cure rate of only about 20%). If it were possible to make the treatment easier to complete (perhaps a time-release injectible system, or a transdermal system) then the number of MDR cases would decrease.
(TB4) A drug delivery system for the antibiotic.
Development of a Syphilis Testing Station for Remote Clinics
There are approximately 12 million new cases of syphilis worldwide each year, according to World Health Organization estimates. The greatest number of cases occur in South and Southeast Asia followed by sub-Saharan Africa.
Syphilis is the classic example of an STD which can be successfully controlled by public health measures: a simple to use and highly sensitive diagnostic test is available, as is a highly effective antibiotic to which resistance has not developed. If untreated, however, syphilis may lead to nerve damage, arterial wall damage, and mental disorientation, and eventually to death. Many of the syphilis cases are asymptomatic, so the patients do not seek treatment. In order for the treatment of this disease to be effective, there must be wide spread screening and treatment of the general population.
The screening process for syphilis involves a serological test in which the presence of anti-bodies is detected. One of the simpler methods for doing this is by using a card agglutination test. A small sample of the patients serum is applied to an area of a card and a antigen is added. The card is shaken for a prescribed amount of time and there is a visible reaction if the anti-bodies are present.
The following equipment is required:
(S1) a device for separating serum from red blood cells
(S2) a device for shaking the card during the test.
In some immunoassays, it is important to monitor the relative strength of the infection, so the patient's progress can be monitored. This is done by diluting the serum sample and finding the weakest dilution which still shows a positive reaction. This process is tedious, involving the measurement of small quantities of serum, diluting, mixing and repeating several times.
(S3) a device for performing dilution tests
Development of a Water Treatment System
Many of the world's heath problems can be attributed to unsafe water supplies. In many African nations, less than fifty percent of the population has access to safe drinking water. In some countries it is less than twenty percent.
In addition to safe drinking water, clean water is required for the operation of the clinic-- for washing and maintaining good hygiene. In the clinic laboratory, many of the reactions require pure water either to mix reagents or dilute samples. It is important that this water is not contaminated in order for the tests to be accurate.
The following water treatment systems are required:
(WT1) Device for providing safe drinking water
(WT2) Device for providing clean, sterile water
(WT3) System for treating waste water
Development of a Computerized Diagnostic Tool for Sexually Transmitted Diseases
AIDS/HIV is one of the biggest issues in health care in Africa. The continent is being devastated by the disease. In some regions they predict that one quarter of the population will die of AIDS by the year two thousand. The spread of the human immunodeficiency virus (HIV) is accelerated by as much as ten times by the presence of sexually transmitted diseases (STD's). These diseases can be treated, and through proper STD management, the spread of HIV slowed down.
In the syndromic method for diagnosing and treating STD's, the nurse follows a flow chart to determine the most likely cause of illness and the appropriate treatment. The Ministry of Health in Botswana is considering using computers to facilitate the syndromic method of diagnosis at the primary hospitals. They are interested in a small hand held computer system to analyze symptoms and store data.
(CD1) Computerized Diagnostic Program
This page is maintained by Amy Smith,
mmadinot@mit.edu