zika virus
DESCRIPTION
Knowledge on a new diseeaseTRANSCRIPT
Zika virus
An Emerging Pathogen
Definition
Zika virus (ZIKV) is a
mild, short lasting febrile
Illness.
History
ZIKV was first discovered in April1947 when a
research rhesus monkey living in the Zika forest
Uganda developed an unknown febrile illness.
Conducted studies established that ZIKV was
endemic to Africa and Asia. It was first isolated
in humans in 1952 in Uganda and Tanzania.
Spread of ZIKV
In April - July 2007 the first outbreak of ZIKV
outside Africa and Asia was reported. This
occurred on the Yap island in the federated state
of Micronesia. It was then identified in French
Polynesia in 2013 and the most recent confirmed
outbreak outside Africa and Asia was in April
2015 in Brazil.
ZIKV Outbreaks
Since its first discovery in Uganda, ZIKV has
been detected in Nigeria, Egypt, Gabon,
Senegal, Sierra Leone, Tanzania, India, Pakistan,
New Caledonia, Easter Island, Indonesia,
Malaysia, Philippines, Thailand, Vietnam, Cook
Island, Yap Island, French Polynesia and Brazil.
ZIKV Outbreaks Cont’d
On 7 May 2015, the Pan American Health
Organization issued an alert recommending that
member states, vulnerable to the introduction of
ZIKV, establish and maintain appropriate
measures for surveillance, control and clinical
management of ZIKV infection.
Agent
ZIKV is a member of the flavivirus
genus and flaviviridae virus family. It is
closely related to Dengue, Yellow Fever,
West Nile and Japanese Encephalitis
Virus.
Photo of Flavi Virus
Vector
Aedes Africanus: ZIKA forest
Aedes Aegypti : Malaysia
Aedes Hensilii : Yap Island
ZIKV was later isolated in Aedes Vitattus,
Aedes Apicoargenteus, Aedes Furcifer and
Aedes Luteocephalus
Photo of Vector
Aedes Mosquito
Reservoir
During studies of yellow fever in the
Zika forest of Uganda, a rhesus monkey
who was tethered in a tree developed a
fever. Serologic studies later identified
the ZIKA Virus. To date the monkeys
still remain the only reservoir.
Rhesus Monkey
Mode of Transmission
Transmission is via the bite of the Aedes
Aegypti mosquitoes. However the Aedes
Hensilli was the predominant mosquito
species identified.
Human to Human Transmission
In 2009 professor Brian Foy a university
biologist contracted ZIKV in Senegal. On his
return to Colorado he became ill and later on his
wife also became ill with similar clinical
manifestations. Hence he proved that Zika Virus
could be sexually transmitted between humans.
Clinical Presentation
Fever (Between 37.8˚C-38.5˚C) Conjunctivitis Arthralgia Maculo-Papular Rash ( often starting on the
face and spreading) Myalgia Headaches (Retro-Ocular headaches) Diarrhoea
Diagnosis
Incubation period is usually between 3 -12 days
with illness lasting 2-7 days. The virus can be
detected during the first five (5) days after the
establishment of the clinical picture (acute
phase). RT-PCR (the reverse transcription-
polymerase chain reaction) test is done to detect
viral RNA.
Diagnosis Cont’d
Serologic Test (ELISA or Inmunofluerescence) :
to detect specific IgM or IgG against Zika Virus.
This could be positive after 5 – 6 days following
the onset of symptoms.
PRNT (Plaque Reduction Neutralization Test):
Confirmation of positive results.
Treatment
There is no vaccine or specific antiviral
treatment for ZIKA viral infection. Treatment
is symptomatic and supportive. This includes
rest, use paracetamol alone or with codeine for
pain and fever. Avoid Aspirins, Ibuprofen and
other anti-inflammatory drugs.
Treatment Cont’d
The use of antihistamines to control pruritis
is recommended in cases of maculopapular
rashes.
Drink plenty fluids to replenish lost from
sweating, vomiting and other insensible
loses.
Complication
Following the outbreak of the Zika virus a noted
increase in autoimmune and neurologic diseases
were observed. Researchers identified 73 cases
in a population of 270,000. Guillian-Barre
Syndrome accounted for 42 cases.
Prevention
Aedes Aegypti mosquitoes lay eggs in
man-made, water filled receptacles such
as water tanks, buckets, tyres, machinery,
pet water dishes and pot plant drip trays,
with mosquito eggs able to survive in
dried-out containers for up to 12 months.
Prevention Cont’d
Eliminate potential breeding sites Empty and spray insecticide to any old unused
container that has held water e.g. tyres, plastic containers, black sheet plastic, buckets or pot plant drip trays.
Store any containers upside down and undercover or under a domed tarpaulin in good repair. Punch holes in tins before discarding
Prevention Cont’d
Avoid using saucers or drip trays under pot plants. Let pots drain directly onto the ground or make sure saucers are emptied at least once/week. Wipe their inner surface firmly with a cloth several times or fill with sand, or spray with insecticide or apply methoprene insecticide pellets
Prevention Cont’d
Empty bird baths and pet drinking water at least weekly and spray with insecticide, or use methoprene pellets
Cover and completely seal septic tanks, rainwater tanks or other large water storage containers
Prevention Cont’d
Use methoprene briquettes in unsealed tanks as a temporary measure
Ensure roof gutters drain freely so that pools of water are not left at any low points. Throw a small amount of methoprene pellets on to the roof above problem gutters
Prevention Cont’d
NB:.
Fishponds with fish do not
breed mosquitoes. Tadpoles do not
eat mosquito larvae.
Prevention Cont’d
Personal Protection
To reduce the risk of mosquito bites in
ZIKV affected areas:Wear loose, light-coloured protective
clothing in outdoor situations, covering feet, legs and arms.
Prevention Cont’d
Use personal repellents containing DEET or picaridin on areas of exposed skin in combination with protective clothing
Use electric insecticide impregnated vapour pads in indoor or enclosed areas.
Prevention Cont’d
Avoid scents on the body, such as perfume, deodorants and sweat, since these can attract mosquitoes
Use electric insecticide impregnated vapour pads in indoor or enclosed areas
Prevention Cont’d
Avoid being outdoors between dusk and dawn to avoid mosquito bites, particularly in poorly lit areas, rural areas, or the outskirts of large towns
If accommodation is not well screened, sleep inside mosquito netting.
Use insecticide impregnated bed nets and clothing in high risk areas.
Public Health Implication
Zika virus is considered an emerging infectious
disease with the potential to spread to new areas
where the Aedes mosquito vector is present. The
discovery of ZIKV in Brazil is testimony to, the
potential for travel or commerce, to spread the
virus across large distances.
Public Health Implication Cont’d
The Caribbean, with our tropical climate, has
long been susceptible to mosquito- borne
diseases such as Yellow fever, Malaria, Dengue
fever and, most recently, Chikungunya. Now we
must be alert for the approaching Zica Virus
Public Health Implications
Bearing in mind that Aedes, a known agent of
the ZIKV is endemic to the Caribbean, the
approaching rainy season, the Carnival festival
which attract tourist, Commercial Activities, the
laboratory capacity to confirm suspected Zika
cases should be taken into account.
Public Health Implication Cont’d
Most importantly the potential neurological and
auto-immune complications that might require
specialised healthcare capabilities and treatment
chiefly ICU care, given our limited bed
Capacity, require keen consideration facing a
large-scale Zika outbreak.
Conclusion
To guarantee prevention success, it is
imperative to involve inter-sectoral
participation and collaboration at all levels of
government including: health, education,
environment, social development and
tourism sectors, among others.
Conclusion Cont’d
We also rely on support of non-governmental
organizations (NGOs). Communication channels
must remain open and community participation
should be mobilized. It is important to provide
clear, good quality information to the public
about this disease via communication campaigns.
Conclusion Cont’d
Vigilance must be enhanced towards imported
cases of ZIKV infection in St. Vincent and the
Grenadines especially with Carnival closely
approaching. Early detection of cases is
essential to reduce the risk of transmission.