Zoonotic diseases neglected for decades.

As part of a study to analyse changes in global health priorities at the global level of the resolutions adopted at the World Health Assembly – the decision making body of the WHO – the relative neglect of endemic zoonotic diseases has been highlighted. This work has recently been published in PLOS NTDs, and has received widespread media attention.

The eight diseases of interest (anthrax, bovine tuberculosis, brucellosis, cysticercosis, echinococcosis, human African trypanosomiasis (HAT), leishmaniasis, rabies) are part of the group termed Neglected Zoonotic Diseases (NZDs) at an international meeting in 2005, so called as they are “not adequately addressed” at national and international levels. Zoonotic diseases are defined as diseases that are transmissible between humans and animals.

In the last decade, the Neglected Tropical Diseases (NTDs) have received increased global attention, and recent events celebrated the increased advocacy and control that has occurred. The research highlighted that these diseases have received relatively little attention at the global policy level, living up to their neglected title. In developing countries where these diseases remain endemic and resources are limited, the control of these diseases is limited as other high profile diseases are prioritised.

Some of the diseases have high fatality and cause a high number of deaths globally each year. For example, rabies causes an estimated 60,000 deaths worldwide, yet this disease remains neglected despite evidence that the disease can be effectively controlled through dog vaccination.

Neurocysticercosis is the greatest cause of preventable epilepsy worldwide, causing an estimated 30% of the 17 million cases of epilepsy in areas where the causative parasite is endemic. This disease can be controlled through sanitation and improved pig husbandry, and improved diagnosis of human infection, requiring a multi-sector approach.

Following the London Declaration on NTDs, there has been increased focus on NTD control. Of the NZDs, only leishmaniasis and HAT are included in the ten diseases which are the focus of the declaration, meaning that the other diseases are not benefitting from the increased Research and Development and drug donations that the other NTDs are experiencing as a result of the declaration. This study highlighted three diseases in particular that are not included in the WHO NTDs. Anthrax, brucellosis and bovine tuberculosis have therefore not received the increased attention that the other NTDs have seen. Upon the inception of the WHO in 1948, around twenty zoonotic diseases were determined to be diseases of priority in the WHO, including bovine tuberculosis and brucellosis. Despite this, there have not been any resolutions adopted for these diseases since 1950. For these diseases, effective and simple control methods exist, meaning that they are no longer endemic in many developed countries. It is therefore astonishing to many that they remain neglected.

It seems that these diseases are particularly neglected due to the complexities of controlling diseases that affect both humans and animals, and the required communication and collaboration between human and animal health sectors, both at community and ministerial levels, that is sometimes lacking. This despite the dual benefits that would be received by both human and animal health sectors upon increased effective control methods.

The international attention that has been received following the publication of this research may be indicative that the neglect of these diseases – some of which are well known and well controlled in some countries – may be something which is surprising, but that there is desire to reduce this neglect and therefore the deaths that occur as a result. In order to reduce this neglect, we must see increased cooperation and communication between human and animal sectors at all levels, and efforts to increase the advocacy for the control of these diseases.

Ms Hayley Mableson is in the final stages of completing a PhD from the University of Edinburgh. Her research to date has focussed on global health advocacy and its application, with particular emphasis on the neglected tropical and zoonotic diseases.