Emerging and re-emerging infectious diseases

INTRODUCTION

There has been world wide explosion of infectious diseases with emerging diseases such as HIV/AIDS pandemic as well as old diseases like cholera, tuberculosis, dengue, or malaria. These infectious diseases are on a sudden increase due to many factors amongst which; climate change, transformation of ecosystems, socio-economic problems and Public health systems deterioration in many countries in the world. Generally, numerous diseases have emerged and re-emerged (Sanjeev et al., 2012). Sanjeev and collaborators (2012) hold to the fact that the so called ‘exotic agents’ constitutes a big threat to our Public health systems which would be justified by limited experience and lack of appropriate resources. Most of the agents causing emerging and re-emerging infectious diseases are zoonotic of origin, transmitted from animals to man either directly or indirectly through vectors. More so, according to the World Health Organization (WHO) in its 2007 report, infectious diseases are emerging at a rate that have not been registered before, noting that about forty infectious diseases have been discovered since 1970. The WHO added that emerging infectious diseases could rapidly spread and create global epidemics given the movement of people around the world (WHO, n.d). In the same optic, Heymann (n.d.) considers the microbial world, complex, dynamic and constantly evolving while noting that infectious agents multiply rapidly, frequently mutate and adapt to new environments. To him an infectious disease is said to be emerging “when the disease is caused by a microbe newly identified and not known previously to infect humans. While a re-emerging infectious disease is “when a disease is caused by an infectious agent previously known to infect humans that has re-entered human populations or changed in epidemiology or susceptibility to anti-infective drugs.

Emerging and re-emerging parasitic infectious diseases are not left out as they are a call for concern in recent times. Parasites impair the health and development of millions of people across the globe causing high risk of illness and death (Chomicz et al., 2016). Chomicz and collaborators (2016) equally reiterated in their study that not only parasites that infect the human host should be taken into consideration, but also those that rarely colonize the human organism in a given area of the world. The latter, which could inflict morbidity and mortality as they may be poorly diagnosed or left untreated. They equally added that re-emerging and emerging parasites have become an increasing worldwide problem in recent times, linked to many mistakes and uncertainties in diagnosis.

Emerging infectious diseases (EIDs) pose a significant threat to global health security. Past experience shows that outbreak of these diseases could not only potentially cause large numbers of human deaths as they spread, but also have huge social and economic impact in today’s interconnected world. Unfortunately, many of these diseases do not yet have any cure, and healthcare providers are also often victims of such diseases. During the past 30 years, more than 30 new organisms have been identified worldwide and many of them have originated at the level of human-animal interface, stated the WHO regional director for South-East Asia in the World Health Organization’s guide to emerging and re-emerging infectious diseases and zoonosis (2014). In fact, in spite an increase of 22 years in life expectancy in low income countries between 1960 and 1995, infectious diseases continue to be the leading cause of morbidity and mortality. Nearly 30% of all deaths in developing countries are of people aged 15-59 years. This represents a problem of premature adult mortality with strong economic implications. Most of these deaths are due to infectious diseases. This group of diseases accounts for 90% of avoidable mortality in developing countries. The impact of infectious diseases on national economies is overwhelming. The evidence generated recently by the Commission on Macroeconomics and Health conclusively showed that the impact of health on economic development has been underestimated. Health has both consumption and investment aspects. It is valued for its own sake and is a means to achieve other goals including generating good income. Common health problems, viz, infectious diseases impact productive activities and unexpected outbreaks of emerging infectious diseases can devastate national economies (WHO Regional Office South-East Asia, 2005).

Most studies espouse that climate change, transformation of ecosystems, mutation of agents, human activity, break down of or inadequate health measures, bioterrorism amongst many others as factors that influence emergence and re-emergence of infectious diseases.

Prevention and control of emerging and re-emerging infectious diseases remain a complex task and requires an integrative and multidisciplinary approach, molecular techniques and traditional epidemiological investigations to define the problem, as well as management strategies that will be effective for these infections. Education and behavioral changes are critical for the success of both prevention and control of these diseases. More so, given that varying socio-economic levels of populations around the world and the potential of health systems, targeting these diseases is rendered complex that is why more infancies need to be given on the identification, treatment and control of these infections (Kumar et al., 2016).

TABLE OF CONTENTS

INTRODUCTION.. 1

DEFINITION OF TERMS. 3

II-1. Infectious diseases: 3

II-2. Emerging infectious diseases (EIDs): 3

II-3. Re-emerging Infectious Diseases (ReIDs). 3

II-4. Zoonotic diseases. 4

BRIEF REVIEW OF SOME EMERGING AND RE-EMERGING INFECTIOUS DISEASES. 4

III-1. Emerging and re-emerging parasitic diseases. 4

III-1.1. Cryptosporidiosis. 4

III-1.2. Cysticercosis. 8

II-1.3. Gnathostomosis. 10

II-1.4. Acanthamoeba Keratitis (AK) 12

III-1.5. Echicococcosis (Echinocociasis, Hydatidosis, Hydatid disease. 13

III-1.6. Toxoplasmosis. 14

III-1.7. Cyclosporiasis. 16

III-1.8. Trypanosomiasis. 16

III-1.9. Schistosomiasis (Bilharzia). 19

III-1.10. Ectoparasitic diseases. 21

III-2. Emerging and Re-emerging Viral diseases. 25

III-2.1. Ebola virus disease. 25

III-3. Emerging and Re-emerging Bacterial diseases. 27

III-4. Emerging and reemerging fungal infections. 28

IV. FACTORS CONTRIBUTING TO EMERGENCE AND RE-EMERGENCE (WHO, 2007; Heymann, n.d.) 29

V. PREVENTION OF EMERGING AND RE-EMERGINGING INFECTIOUS DISEASES (WHO, 2007; WHO IHR, 2005) 32

VI. CONCLUSION…………………………………………………………………………………………………………………………….25

VII. REFERENCES. 34

VIII. ANNEX.. 38