Budke Focusing Global Attention on Neglected Tropical Diseases
Making a Difference
Committed to increasing awareness about neglected tropical diseases (NTDs) is Dr. Christine M. Budke, an associate professor in the Department of Veterinary Integrative Biosciences at the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM). Her interest in the field began when she was a veterinary student at Purdue University. “I did a variety of international externships, and one of them happened to focus on parasites,” she said. “After that I was hooked.”
After veterinary school, Budke moved to Europe, where she obtained a Ph.D. in epidemiology from the University of Basel in association with the Swiss Tropical and Public Health Institute and the University of Zurich. During her graduate studies, she spent much of her time conducting infectious disease fieldwork on the Tibetan Plateau of western China.
Budke now works to better elucidate the socioeconomic impact of two parasitic NTDs: echinococcosis and neurocysticercosis (NCC). Both of these diseases are zoonotic, meaning they are transmissible between animals and people.
One goal of Budke’s work is to give the research community and policymakers a better feel for the true impact of these diseases on different parts of the world. She hopes this knowledge will help promote better allocation of resources.
“You can have many cases of a disease that are fairly mild,” said Budke. “On the other hand, you can have a relatively small number of cases, such as has occurred with the Ebola outbreak, with a high mortality rate. Our goal is to find ways to better quantify the true impact of these diseases on a society.”
One way to better understand the true impact of disease is to create a common metric to compare diseases. The DALY, or Disability Adjusted Life Year, is one such tool. It measures morbidity, mortality, and duration, as well as the severity of clinical symptoms of a disease. This enables researchers to compare very different diseases-such as the common cold and an Ebola infection.
One DALY can be thought of as one lost year of “healthy” life. The sum of these DALYs across the population, or the burden of disease, can be thought of as a measurement of the gap between current health status and an ideal health situation where the entire population lives to an advanced age, free of disease and disability, according to the World Health Organization. “If you are able to incorporate mortality and the severity of the disease into that metric, you can actually compare the impact of Ebola and the common cold or a parasitic disease with a viral disease because you are using a common language and a common tool,” said Budke.
The Big Two
Budke’s work is a prime example of the global One Health Initiative. The diseases on which her work is focused pose a double threat to the societies where they manifest, because both humans and their livestock can become infected. “If you have a community affected by echinococcosis, then you have individuals who are ill and may not be able to work and who are impacted physically as well as emotionally from their disease,” Budke said. “If their animals also have the disease, and the animals contribute to their livelihood, as is true in many communities, the impact can be devastating.”
An insidious disease, echinococcosis causes cystic lesions in the liver, lungs, or both in people who do not become ill immediately, but whose health slowly declines over a period of time. This disease is particularly problematic in pastoralist and low-income communities around the world. “The causative parasite is a type of tapeworm, but they are unlike the very long tapeworms that most people envision,” Budke said. “They are very tiny-the size of a grain of rice-but they can cause serious damage.”
Eliminating echinococcosis is extremely difficult because so many animal species can become infected with the cyst stage of the parasite. Large free-roaming dog populations, which carry the adult stage of the parasite, also make control a challenge in some locations. Although dog deworming is very effective, it must be repeated regularly to prevent re-infection; repeated deworming, however, can be difficult in resource-poor areas. To date, there have been few coordinated efforts globally to control this NTD. More recent advances have focused on developing a sheep vaccine; however, thus far, vaccines are not readily available.
The other tapeworm that Budke studies is Taenia solium, which causes NCC. This condition, which is believed to be one of the leading causes of epilepsy in the developing world, is especially found in sub-Saharan Africa, Asia, and parts of South America. Like echinococcosis, this parasite also affects both people and livestock-pigs in this case. Poor sanitation can result in people ingesting parasite eggs that are shed by infected individuals, which can then develop into cysts in the central nervous system, resulting in epilepsy, stroke, or dementia.
Budke noted that this infection can have a major impact on a community, in terms of illness and the stigma some societies still attach to those with epilepsy. Although epilepsy can be caused by other factors (or have no known cause at all), NCC is a leading cause of epilepsy cases, especially in low socioeconomic status pig-rearing areas, as pigs are vital for the parasite’s life cycle.
Because these conditions are chronic and zoonotic and because they disproportionately affect socioeconomically disadvantaged pastoral and agricultural communities, efforts to study and control echinococcosis and NCC remain substantially underfunded. Control of these diseases, Budke explained, requires a multidisciplinary approach. However, agricultural and public health funding agencies often wait for each other to take the lead. The impact on communities is also undervalued because of lack of information; diagnosis of echinococcosis and NCC in humans usually requires medical imaging, which is rarely available in developing countries, and infection in livestock at slaughter is seldom monitored.
Although there are human cases of echinococcosis and NCC in the United States, the vast majority of these cases are in people who were infected elsewhere. “Primarily what you are seeing are these diseases affecting the immigrant population,” Budke said. “The biggest impact is the drain on the health care system because these can be fairly expensive diseases to treat.”
Work Underway
Budke works with a number of global initiatives focused on estimating the effect of these parasites on societies in which they are found. Other groups within these initiatives are working on other parasitic agents, as well as toxins and chemicals, bacteria, and viruses. Noting which diseases are impacting a particular country’s population can aid policymakers in determining priorities.
In the last 10 years, Budke noted, there has been an effort to put NTDs “on the map,” so to speak. “I think we are at least starting to go in the right direction to finally address some of these conditions,” she said. Part of the challenge, however, is that when something “big, new or exciting,” such as avian flu or Ebola, hits the news, it can be dramatic and get an abundance of attention. “A lot of these NTDs have been around for a very long time. They tend to be chronic. They just don’t grab the same attention as some higher-profile diseases; therefore, they tend to be forgotten.”
As the world becomes more aware of NTDs and as people in Budke’s field continue to work on solutions for positive change, her work becomes evermore important. “We are trying to get the larger population to understand what is going on and to become aware of the populations that are impacted,” she said.
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Budke’s work is a prime example of the global One Health Initiative. The diseases on which her work is focused pose a double threat to the societies where they manifest, because both humans and their livestock can become infected. “If you have a community affected by echinococcosis, then you have individuals who are ill and may not be able to work and who are impacted physically as well as emotionally from their disease,” Budke said. “If their animals also have the disease, and the animals contribute to their livelihood, as is true in many communities, the impact can be devastating.”
An insidious disease, echinococcosis causes cystic lesions in the liver, lungs, or both in people who do not become ill immediately, but whose health slowly declines over a period of time. This disease is particularly problematic in pastoralist and low-income communities around the world. “The causative parasite is a type of tapeworm, but they are unlike the very long tapeworms that most people envision,” Budke said. “They are very tiny-the size of a grain of rice-but they can cause serious damage.”
Eliminating echinococcosis is extremely difficult because so many animal species can become infected with the cyst stage of the parasite. Large free-roaming dog populations, which carry the adult stage of the parasite, also make control a challenge in some locations. Although dog deworming is very effective, it must be repeated regularly to prevent re-infection; repeated deworming, however, can be difficult in resource-poor areas. To date, there have been few coordinated efforts globally to control this NTD. More recent advances have focused on developing a sheep vaccine; however, thus far, vaccines are not readily available.
The other tapeworm that Budke studies is Taenia solium, which causes NCC. This condition, which is believed to be one of the leading causes of epilepsy in the developing world, is especially found in sub-Saharan Africa, Asia, and parts of South America. Like echinococcosis, this parasite also affects both people and livestock-pigs in this case. Poor sanitation can result in people ingesting parasite eggs that are shed by infected individuals, which can then develop into cysts in the central nervous system, resulting in epilepsy, stroke, or dementia.
Budke noted that this infection can have a major impact on a community, in terms of illness and the stigma some societies still attach to those with epilepsy. Although epilepsy can be caused by other factors (or have no known cause at all), NCC is a leading cause of epilepsy cases, especially in low socioeconomic status pig-rearing areas, as pigs are vital for the parasite’s life cycle.
Because these conditions are chronic and zoonotic and because they disproportionately affect socioeconomically disadvantaged pastoral and agricultural communities, efforts to study and control echinococcosis and NCC remain substantially underfunded. Control of these diseases, Budke explained, requires a multidisciplinary approach. However, agricultural and public health funding agencies often wait for each other to take the lead. The impact on communities is also undervalued because of lack of information; diagnosis of echinococcosis and NCC in humans usually requires medical imaging, which is rarely available in developing countries, and infection in livestock at slaughter is seldom monitored.
Although there are human cases of echinococcosis and NCC in the United States, the vast majority of these cases are in people who were infected elsewhere. “Primarily what you are seeing are these diseases affecting the immigrant population,” Budke said. “The biggest impact is the drain on the health care system because these can be fairly expensive diseases to treat.”
Budke works with a number of global initiatives focused on estimating the effect of these parasites on societies in which they are found. Other groups within these initiatives are working on other parasitic agents, as well as toxins and chemicals, bacteria, and viruses. Noting which diseases are impacting a particular country’s population can aid policymakers in determining priorities.
In the last 10 years, Budke noted, there has been an effort to put NTDs “on the map,” so to speak. “I think we are at least starting to go in the right direction to finally address some of these conditions,” she said. Part of the challenge, however, is that when something “big, new or exciting,” such as avian flu or Ebola, hits the news, it can be dramatic and get an abundance of attention. “A lot of these NTDs have been around for a very long time. They tend to be chronic. They just don’t grab the same attention as some higher-profile diseases; therefore, they tend to be forgotten.”
As the world becomes more aware of NTDs and as people in Budke’s field continue to work on solutions for positive change, her work becomes evermore important. “We are trying to get the larger population to understand what is going on and to become aware of the populations that are impacted,” she said.
