Please help me to solve this question and please type! Thank you using the CDC a
ID: 184944 • Letter: P
Question
Please help me to solve this question and please type! Thank you
using the CDC and WHO web site for parasite infections. Millions of people are infected globally by these parasites and thousands to millions die annually, particularly children.
A)What geographic areas have witnessed emerging, re-emerging, reduced transmission or elimination of infections?
B) On the CDC web site view the vaccines listed in the section "Vaccines by disease". a) Which of the different pathogen groups have the most vaccines (routine and non-routine vaccines)?
Explanation / Answer
A) Historically, over the centuries, human populations have experienced major epidemics of infectious diseases. Imported smallpox microbes carried by explorers were responsible for 10-15 million deaths in 1520-1521, effectively ending Aztec civilization. Other Amerindian and Pacific civilizations were destroyed by imported smallpox and measles. Similar to smallpox, plague - a disease caused by bacteria and spread by rats had eliminated as much as a third of the European population over a five year period in the 14th century. By the middle of the 20th century, infectious diseases were no longer considered as the major cause of mortality in developed countries.
Establishment of the germ theory and the identification of specific microbes as the causative agent of a wide variety of infectious diseases led to enormous progress, notably the development of vaccines and antimicrobials1. The eradication of smallpox reinforced the perception that infectious diseases could be eliminated. Improved sanitation, clean water and better living conditions along with vaccines and antimicrobial agents brought many infectious diseases under control. While the old world communicable diseases are ebbing, a slew of newer and hitherto unknown set of communicable diseases like avian influenza, SARS, etc. are on a rise10. Moreover, the emergence of drug resistance such as multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis, malaria resistant to artemisinin-combination therapy (ACT) is new global challenges requiring concerted efforts.
Human pathogens emerge and re-emerge due to an interaction of multiple complex factors between the host and pathogen each driven by the need to secure the success of the species in changing environments. Adaptation by one partner to exploit new environments will often stimulate the other to modify its characteristics to take advantage of the change. The human encroachment into habitat especially in tropical regions and interface with wildlife can lead to the creation of “hot spots” for the emergence of new pathogens, with a potential for rapid spread among susceptible human populations, facilitated by rapid means of travel and wildlife trafficking. The mutation of a virus strain from animals, as making it infectious to humans, is a common cause of new illnesses in humans. A systematic review conducted to identify factors associated with emergence and re-emergence of human pathogens has shown changes in land use or agricultural practices and changes in human demographics and society as the major drivers associated with emergence and re-emergence of human pathogens.
The Global burden of emerging diseases
The emerging infectious diseases account for 26 percent of annual deaths worldwide. Nearly 30 percent of 1.49 billion disability-adjusted life years (DALYs) are lost every year to diseases of infectious origin. The burden of morbidity and mortality associated with infectious diseases falls most heavily on people in developing countries, and particularly on infants and children (about three million children die each year from malaria and diarrhoeal diseases alone).
A literature survey identified 1,407 species of human pathogens, with 177 (13%) species regarded as emerging or re-emerging. Distribution of emerging and re-emerging pathogens by groups shows that 37 percent of emerging and re-emerging pathogens are viruses and prions followed by protozoa (25%). This indicates that emerging and re-emerging pathogens are disproportionately viruses. Examples of some recent emerging and re-emerging infections. In addition, emergence of microorganisms resistant to antimicrobials to which these were previously sensitive to is cause of concern. Cases with such infections often fail to respond to the standard treatment, resulting in prolonged illness and increased risk of death. According to WHO, 440,000 new cases of multi-drug resistant tuberculosis (MDR-TB) emerge annually, causing at least 150,000 deaths6. A more virulent form called extensively drug-resistant tuberculosis (XDR-TB) has been reported from 64 countries. Another example of global concern relates to the spectre of falciparum malaria resistant to artemisinin combination therapy (ACT) emerging at the Cambodia-Thai border which has a potential to spread across countries.
Developing countries such as India suffer disproportionately from the burden of infectious diseases. India the second most populous country in the world is in the midst of a triple burden of diseases; the unfinished agenda of communicable diseases, non-communicable diseases linked with lifestyle changes, and the emergence of new pathogens and overstretched health infrastructure. Communicable diseases account for nearly half of India's disease burden. Many infections are associated with poor sanitation, contaminated food, inadequate personal hygiene, or access to safe water and lack of basic health services- conditions common to large parts of India. Favourable environmental, demographic and socio-economic factors further put India at a risk of epidemics of emerging infections. Over the years increase in cases of drug-resistant malaria, tuberculosis, HIV-TB co-infections and epidemics of avian influenza have demonstrated the vulnerability of India to the threat of evolving microbes.
Emerging infections in India: Trends and epidemiological features
In the recent past, India has witnessed many large outbreaks of emerging infections and most of them were of zoonotic origin. A review of the list shows that of the eight aetiological agents, five are of viral origin. Six of these infections are of zoonotic nature.
A large-scale cholera outbreak occurred in India in 1992 starting in southern peninsular India and spreading both inland and along the coastline of Bay of Bengal. Vibrio choleraeO139, a new serogroup was associated with this epidemic cholera15. Reports of cholera outbreak due to this new serogroup have come from various parts of the country. Patients infected with O139 strains were much older than those infected with O1 strains. Over the previous one decade, O1 and O139 serogroups have coexisted in much of the cholera endemic areas in India and elsewhere.
The 1994 plague outbreak in Surat in Gujarat State created an unprecedented level of panic leading to population exodus and internal migration, contributed in part by local and international media reports, and to considerable negative social, political, and economic impact. Plague infection continues to exist in sylvatic foci in many parts of India which is transmitted to humans occasionally. This has been demonstrated with focal outbreaks of plague in India in 1994, 2002 and 2004. Epidemiological investigations have attributed these recurrences to spillover from an epizootic cycle of plague in wild rodents to commensal rodents driven by climate variation. Recent analysis of data from Kazakhstan shows that warmer springs and wetter summers increase the prevalence of plague in its main host, the great gerbil. The National Center for Disease Control (NCDC) has identified four sylvatic foci in India; the tri-junction of Karnataka, Andhra Pradesh and Tamil Nadu, later Beed belt in Maharashtra, Rohru in Himachal Pradesh and Uttarakhand. The plague outbreak in Surat led not only to nationwide panic but to a near international isolation of India. As a result, the country incurred direct economic losses to the tune of US $ 1.7 billion.
The incidence of diphtheria, a vaccine-preventable disease during 1980 was about 39,231, it reduced to 2817 cases in 1997. However, in the past two decades, there has been a sudden increase in diphtheria cases with more than 8000 cases reported in 2004. The primary immunization coverage for diphtheria has remained between 56 to 72 percent in the past two decades according to WHO UNICEF estimate. The three rounds of National Family Health Surveys (NFHS) also show that DPT 3 coverage during 1992-2006 was only 52-55 percent. Persistence or resurgence of diphtheria in the country seems mainly due to low coverage of primary immunization as well as boosters. There have been reports of diphtheria outbreaks from various States including Delhi, Andhra Pradesh, Assam, Maharashtra, Chandigarh, Gujarat. An epidemiological age shift has been noted in these outbreaks, with the disease now affecting older children (5-19 yr) and adults. Majority of the cases were reported from children who were unimmunized or partially immunized against diphtheria.
B) 1. Routine vaccination
Diphtheria, tetanus, and pertussis Hepatitis B Haemophilus influenzae type b Human papillomavirus a Measles, mumps and rubella Pneumococcal disease Poliomyelitis Rotavirusa Tuberculosis (BCG)c Varicella
2. Selective use for travellers
Cholera Hepatitis Ad Japanese encephalitisd Meningococcal diseased Rabies Tick-borne encephalitis Typhoid fever Yellow fever
3. Mandatory vaccination
Yellow fever (see country list) Meningococcal disease and polio (required by Saudi Arabia for pilgrims