Microbiology

1. CHAPTER 32
EMERGING
INFECTIONS
Universities Press
3-6-747/1/A & 3-6-754/1, Himayatnagar
Hyderabad 500 029 (A.P.), India
Email: info@universitiespress.com
marketing@universitiespress.com
Phone: 040-2766 5446/5447
Part III
Microbiology as Applied to Infectious
Diseases

2. Dr Sonal Saxena, MD
Director Professor and Head of the Department of Microbiology
Maulana Azad Medical College,
New Delhi
and
Dr Amala A Andrews, MD
Maulana Azad Medical College,
New Delhi
UNIVERSITIES PRESS PVT LTD.

3. DEFINITIONS
Emerging infectious diseases: These are diseases that have
appeared for the first time in a population or that did not exist
previously in an area but are rapidly increasing in incidence in
that geographical range
Re-emerging infections: These are infections that caused
recognised health problems in the past and subsequently
dropped in incidence to such low levels that they were no longer
considered public health problems only to re-emerge with an
upward trend in incidence or prevalence, either in the same
geographic area or worldwide.
Two-thirds of emerging infections originate from animals—both
wild and domestic, i.e., they are zoonotic
UNIVERSITIES PRESS PVT LTD.

4. FIG 32.1 FACTORS CONTRIBUTING TO THE EMERGENCE OF INFECTIONS
UNIVERSITIES PRESS PVT LTD.

5. NEW
INFECTIOUS
DISEASES
UNIVERSITIES PRESS PVT LTD.
Table 32.1 New infectious
diseases recognised since 1997

6. Table 32.2 Emerging and re-emerging infections in India
UNIVERSITIES PRESS PVT LTD.

7. ZIKA VIRUS
India, Zika virus was first reported from the Bapunagar area
of Ahmedabad, Gujarat, January 2017
Positive by RT-PCR; all three cases recovered
The low level of transmission of the Zika virus in an area
may lead to new cases among naïve populations in the
future
Zika virus antibodies have been detected in the Indian
population, indicating protective immunity
UNIVERSITIES PRESS PVT LTD.

8. CRIMEAN–CONGO HEMORRHAGIC FEVER (CCHF)
CCHF was reported for the first time in 2011 from Gujarat
As zoonotic in origin with ticks as the vectors
The outbreak was caused by person-to-person transmission in hospitals
UNIVERSITIES PRESS PVT LTD.

9. NIPAH VIRUS
Zoonotic virus
Food-borne disease that is transmitted by the ingestion of
dates contaminated with the urine or saliva of infected bats,
following which, person-to-person transmission occurs
Originated in Malaysia in 1999 and then reached Bangladesh
and the eastern parts of India including Siliguri, West Bengal, in
2001
Human infections range from asymptomatic infection to acute
respiratory infection (mild, severe) and fatal encephalitis
UNIVERSITIES PRESS PVT LTD.

10. CLINICAL
FEATURES
Incubation period: 4–14 days.
Initially fever, headaches, myalgia (muscle pain), vomiting and sore throat
Later, dizziness, drowsiness, altered consciousness and neurological signs
that indicate acute encephalitis
Some people also experience atypical pneumonia and severe respiratory
problems, including acute respiratory distress
Encephalitis and seizures occur in severe cases, progressing to coma within
24–48 hours
Most people who survive acute encephalitis make a full recovery, but long-
term neurologic conditions have been reported in survivors
20% of patients are left with residual neurological consequences such as
seizure disorder and personality changes
A small number of people who recover subsequently relapse or develop
delayed-onset encephalitis
The case fatality rate is estimated to be 40–75%
UNIVERSITIES PRESS PVT LTD.

11. LABORATORY DIAGNOSIS
Clinical history during the acute and convalescent phase of
the disease
Real-time polymerase chain reaction (RT-PCR) assay of
bodily fluids
Antibody detection via enzyme-linked immunosorbent assay
(ELISA)
Treatment
There are currently no drugs or vaccines specific for Nipah
virus infection
Intensive supportive care is recommended to treat severe
respiratory and neurologic complications
UNIVERSITIES PRESS PVT LTD.

12. HUMAN
HANTAVIRUS
In 2005, following the floods in Mumbai, some cases were
found to have IgM antibodies to the virus
It may be that the disease exists in India, but its incidence
is under-reported due to the lack of awareness
Early suspicion and rapid confirmation of diagnosis are
vital in preventing emergence of hantavirus infection in
India
Availability of simple, easy-to-perform and affordable tests
are a basic necessity for proper management
Rapid control measures, which include contact tracing,
quarantine and active surveillance are required to contain
the infection and prevent large-scale outbreaks
Mass vaccination, if available, must be instituted
UNIVERSITIES PRESS PVT LTD.

13. ANTIBIOTIC RESISTANCE
The number of drug-resistant bacteria has increased in the last
decade; this is a cause for great concern
Of major public health concern and considered as emerging
infections are the following:
Multidrug-resistant tuberculosis (MDR and XDR-TB)
Methicillin-resistant S. aureus (MRSA)
Penicillinase-producing N. gonorrhoeae (PPNG)
Vancomycin-resistant enterococci (VRE)
Extended-spectrum beta-lactamase (ESBL)-producing gram-
negative bacteria
Carbapenemase-producing Enterobacteriaceae (CRE)
UNIVERSITIES PRESS PVT LTD.

14. CONTROL OF EMERGING ANTIMICROBIAL
RESISTANCE
Rational use of antimicrobial agents
Infection-control measures in hospitals and control of prescription
Antibiotic stewardship programmes within hospitals are a means to contain emerging
resistance
Creating awareness among the public and restriction of over-the-counter sale of the anti-
infective drugs are other major drives to control the misuse of antibiotics
Antibiotics should be dispensed exclusively on prescription
Price and quality control of the available drugs requires to be monitored by regulatory
authorities
UNIVERSITIES PRESS PVT LTD.