By Pharm. Dominic Korsah Otchere
´A virus is a bad news wrapped in a protein´
Recent focal outbreaks of yellow fever in two regions in Ghana, Brong Ahafo and Volta, is a major public health concern. Yellow fever, an international notifiable disease together with cholera and plague, is a zoonotic flavivirus infection transmitted by Aedes mosquito. The Aedes mosquito is also the vector for dengue fever and the zika virus.
Yellow fever can be recognized from historic texts stretching back 400 years, causing large epidemics in Africa and the Americas during the slave trade. It is also called yellow plague and one of viral haemorrhagic fevers.
Although an effective vaccine has been available for over 60 years, the number of people infected over the last two decades has increased and the disease is now a serious public health issue again. Thirty-four countries, with a combined population of 508 million are at risk in Africa, especially in sub-Saharan Africa. Despite intensified public health campaigns and WHO recommended childhood immunization programs, it has been estimated that more than 200,000 cases with up to 30,000 deaths occur annually globally, the great majority occurring again in Africa. Three transmission cycles have been recognized: sylvatic, intermediate, and urban.
The re-emergence of old viral diseases, such as yellow fever, previously thought to have been under control, and the emergence of new ones, such as ebola, is the current global epidemiological trend. This trend has not only extended the frontiers of infectious diseases, but has also totally changed the health care environment, providing a new focus and direction of international health.
To begin with, the concept of viruses was developed by Dmitrii Ivanowski and Martinus Beijerinck (studying Tobacco mosaic disease) and by Friedrich Loeffler and Paul Frosch (studying foot-and-mouth disease) in 1899. Viruses (and later other acellular infectious agents) have captivated the imagination and attention of countless scientists, health care professionals, policy makers and even politicians since their discovery in the late 19th century due to their ability to cause human diseases.
Viruses are packets of infectious nucleic acid surrounded by protective protein coats, and remain the most efficient of the self-reproducing intracellular parasites. They are a unique group of infectious agents whose distinctiveness resides in their simple acellular organization and replication strategies. A dangerous feature unique to viruses is their ability to infect all types of cells – plants, animals, protists, fungi, bacteria and archael. They range in size from 10nm to 400nm in diameter, and their diversity is in part due to their structural features, especially the nature of their genomes. Strangely, four nucleic acid types can be found in viruses; double stranded DNA, single stranded DNA, double stranded RNA and single stranded RNA. Unfortunately the Linnaean (binomial) system of nomenclature has so far not proved satisfactory for the classification of viruses. In part, this is due to a lack of knowledge of their origin and evolutionary history.
The International Committee on Taxonomy of Viruses (ICTV), the official authority responsible for standardizing viral taxonomy, described almost 2000 viruses in its 8th report, out of which over 400 have been identified as capable of infecting humans. Although the ICTV reports are the official authority on viral taxonomy, many virologist find it useful to group viruses using a scheme devised by Nobel Laureate David Baltimore. The Baltimore system organizes viruses into seven groups and simplifies the vast array of viral life cycles into a relatively small number of basic types.
Some of the world oldest diseases known on record are of viral origin. For instance various Egyptian hieroglyphics, dated approximately 2000 B.C., depicts individuals with wasting, withered legs an hands, which are suggestive of Polio. Virus have emerged as a significant human pathogen since their discovery, and their spectrum keep expanding year after year. They now constitute an important pathogen to the human race, with many more being discovered each year. In addition to viruses, other acellular infectious agents which have the potential to infect humans have also been identified. These entities include viroids and virusoids (consists of RNA only), and prions (made of protein only).
Viral diseases emerge following one of three general patterns: recognition of a new agent, abrupt increase in illnesses caused by an endemic agent, and invasion of a new host population. Some of these factors accounting for these phenomena are increase human exposure to once-obscure pathogens; dissemination of once-localized infections; and changes in viral properties or host responses to infection.
Viruses continue to attract great attention and interest for several reasons. They are responsible for age old life-threatening diseases such as polio, influenza, etc. Currently, six out of the 12 vaccine preventable diseases covered by the Expanded Programme on Immunization (EPI) in Ghana are of viral origin. It must be noted that in spite of concerted global efforts, some of these childhood diseases still pose a great threat to child survival. For instance, measles is still on record to account for 30-40miilion cases with 530,000 deaths annually globally.
Secondly, their ability to cause cancers in humans, and other susceptible animals, remains a major cause for concern. Examples of cancers which have virus has their etiologic agents are Kaposi’s sarcoma (HHV8), Burkitt’s lymphoma (EBV), hepatoma (Hepatitis B and C), Cervical cancer (HPV) and adult T-cell leukemia (HTLV-1). Cancer remains one of the most serious medical problems globally, and the focus of an immense amount of research.
Also, with a few exceptions, only prophylactic or supportive treatment is available for most viral diseases. Collectively, these diseases are some of the most common and yet puzzling of all infectious diseases. The resulting frustration is compounded when year after year familiar diseases of unknown etiology or new diseases become linked to virus infections.
Furthermore, viral diseases are among the re-emerging diseases that pose great public health threat. Examples are rabies, yellow fever, and hepatitis B. Recently the Ministry of Health (MOH) decided to focus on prevention of rabies, through immunization of all pets, particularly dogs and cats, to address the global shortage of ARVs. This strategy, apart from being cost effective, has also been found to be the secret of the success stories of some advanced countries in elimination of
rabies. In 2015, the government spent close to 1 million U.S. dollars in importing ARVs into the country. Recent launch of the WHO guidelines on Blood Transfusion Safety to address to dangers associated with agents such as HIV and Hepatitis B virus, further indicates that the threat posed by these acellular infectious entities are real and dangerous.
Finally, some of the past and recent disease outbreaks, which assumed pandemic dimensions and threatened the survival of human kind are of viral origin. Examples are Ebola virus (1976), HIV (1981), SARS (2003), new avian influenza virus (2005/06), the H1N1(Swine) influenza virus in 2009, zika virus(2015). The HIV is of particular interest since it has been recognized as the greatest pandemic of the second half of the twentieth century and still remains the focus of molecular biology due to its global impact. Influenza has the worst pandemic record for killing approximately 50 million people around the world in 1918; a disaster now traced to the Spanish influenza virus.
It is believed that several viruses are lurking in the wild that with little help from nature could wreak far more loss than will the likely result from AIDS pandemic. Concerns exist about the potential accidental introduction of new viral pathogens from donor animal species into humans. Of potential concern is the possible use of animal organs as xenografts in humans. Because the numbers of available human donor organs cannot meet the needs of all waiting patients, xenotransplantation of non-human primate and porcine organs is considered an alternative.
From the foregoing discussions, it can be inferred that virology has now emerged as a key area that scientists, researchers and health care professionals, especially pharmacists, must re-direct their attention to and focus on. This is because the future of health care services seem to lie in this area. However, virology is a vast area, and only now are scientists beginning to make in-roads into most of its fundamental secrets. The molecular and cellular events underlying the mechanism of most viral diseases and anti-viral agents are still poorly understood. Any profession that masters this emerging area is likely to play a leadership role in health care services in the foreseeable future.
Some colleague Pharmacist have already shown interest in this area by weaving their way into ART Clinics in their facilities and are doing tremendously well. It can confidently be said that pharmacists are the backbone of ART program in Ghana today; a living testimony to our versatility as a profession, and our preparedness to take on more clinical services. Some pharmacists have even gone ahead to formulate herbal preparations which have proven efficacious against the HIV and are even being sold on commercial basis after carefully studied clinical trials.
Going forward, we can confidently say that one of the ways to establish ourselves as professionals is by seeing this emerging trend as an opportunity, rather than a threat, and learning everything we can about it to become experts. There is no expert on what will be. All the experts, are experts on what was. For we are more capable than we think.
Good morning learned Colleagues. Let us see the emergence of viral diseases as an opportunity to advance our practice. For we are more capable than we think.