Travelrelated risks - PowerPoint PPT Presentation

Title: Travelrelated risks


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Travel-related risks Tropical infections
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• The number of people travelling internationally
  is increasing every year.
• According to statistics of the World Tourism
  Organization, international tourist arrivals in
  the year 2005 exceeded 800 million.
• Travel-related risks
• Key factors in determining the risks to which
  travellers may be exposed are
• destination
• duration and season of travel
• purpose of travel
• standards of accommodation and food hygiene
• behaviour of the traveller
• underlying health of the traveller

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MEDICAL CONSULTATION BEFORE TRAVEL

• Travellers intending to visit a destination in a
  developing country should consult a travel
  medicine clinic or medical practitioner before
  the journey at least 48 weeks before the journey
• The consultation will determine the need for any
  vaccinations and/or antimalarial medication, as
  well as any other medical items that the
  traveller may require.

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• Dental and for women gynaecological check-ups
  are advisable before travel to developing
  countries or prolonged travel to remote areas.

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NB!

• ? Avoid uncooked food, apart from fruit and
  vegetables that can be peeled or
• shelled, and avoid fruits with damaged skins.
• ? Avoid dishes containing raw or undercooked
  eggs.
• ? Avoid food bought from street vendors.
• ? Avoid ice cream from unreliable sources,
  including street vendors.
• ? In countries where poisonous biotoxins may be
  present in fish and shellfish,
• obtain advice locally.

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• Boil unpasteurized (raw) milk before consumption.
• ? Boil drinking-water if its safety is doubtful
  if boiling is not possible, a certified,
• well-maintained filter and/or a disinfectant
  agent can be used.
• ? Avoid ice unless it has been made from safe
  water.
• ? Avoid brushing the teeth with unsafe water.
• ? Bottled or packaged cold drinks are usually
  safe provided that they are sealed hot beverages
  are usually safe.

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Malaria

• Malaria in humans is caused by Plasmodium
• P. falciparum, P. vivax, P. ovale, or P.
  malariae.
• All species are transmitted by the bite of an
  infected female Anopheles mosquito.
• Occasionally, transmission occurs by blood
  transfusion, organ transplantation,
  needle-sharing, or congenitally from mother to
  fetus.
• Malaria can be a fatal disease, illness and death
  from malaria are largely preventable.
• Each year 350-500 million cases of malaria occur
  worldwide, and approximately 1 million deaths
  annually

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• Plasmodium falciparum is the agent of severe,
  potentially fatal malaria, causing an estimated
  700,000 - 2.7 million deaths annually, most of
  them in young children in Africa.
• Plasmodium vivax and P. ovale have dormant liver
  stage parasites ("hypnozoites") which can
  reactivate ("relapse") and cause malaria several
  months or years after the infecting mosquito
  bite.
• Plasmodium malariae produces long-lasting
  infections and if left untreated can persist
  asymptomatically in the human host for years,
  even a lifetime.

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• P. vivax malaria can cause rupture of the spleen
  or acute respiratory distress syndrome (ARDS).
• Nephrotic syndrome (a chronic, severe kidney
  disease) can result from chronic or repeated
  infections with P. malariae.
• Hyperreactive malarial splenomegaly (also called
  "tropical splenomegaly syndrome") occurs
  infrequently and is attributed to an abnormal
  immune response to repeated malarial infections.
• The disease is marked by a very enlarged spleen
  and liver, abnormal immunologic findings, anemia,
  and a susceptibility to other infections (such as
  skin or respiratory infections).

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Countries with Malaria Risk

• Travelers to sub-Saharan Africa have the greatest
  risk of both getting malaria and dying from their
  infection.
• However, all travelers to countries with malaria
  risk may get this potentially deadly disease.
• Malaria is transmitted in large areas of Central
  and South America
• the island of Hispaniola (includes Haiti and the
  Dominican Republic)
• Africa
• Asia (including the Indian subcontinent,
  Southeast Asia and the Middle East)
• Eastern Europe
• and the South Pacific

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• NB! According to the Jamaica Ministry of Health
  (MOH) and the Caribbean Epidemiology Center
  (CAREC) report of January 30, the outbreak of
  malaria in Kingston, Jamaica, is ongoing. The
  most recent reported date of onset of illness was
  January 23, 2007. All confirmed infections have
  been caused by Plasmodium falciparum. Jamaica is
  a country where malaria is not considered endemic
  and malaria transmission does not normally occur,
  and where CDC has not previously recommended
  antimalarial prophylactic drugs for U.S.
  travelers.

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Malaria Clinical Presentation

• Malaria symptoms can develop as early as 7 days
  after initial exposure in a malaria-endemic area
  and as late as several months after departure
  from a malarious area, after chemoprophylaxis has
  been terminated.
• Fever and influenza-like symptoms, including
  chills, headache, myalgias, and malaise these
  symptoms can occur at intervals.

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• Malaria may be associated with anemia and
  jaundice
• P. falciparum infections can cause seizures,
  mental confusion, kidney failure, coma, and
  death.

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Pathogenesis

• in humans develops via two phases an
  exoerythrocytic (hepatic) and an erythrocytic
  phase.

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Evolutionary pressure of malaria on human genes

• Sickle-cell disease
• in populations where malaria is endemic, the
  frequency of sickle-cell genes is around 10
• Thalassaemias
• with ß-thalassaemia had a 50 decreased chance of
  getting clinical malaria.
• Duffy antigens
• Plasmodium vivax malaria uses the Duffy antigen
  to enter blood cells.
• G6PD(Glucose-6-phosphate dehydrogenase)
• genetic deficiency in this enzyme results in
  increased protection against severe malaria.
• Human leukocyte antigen system (HLA B53) is
  associated with low risk of severe malaria

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• Plasmodium falciparum infected erythrocyte
  forming arosette, a process associated with
  virulence in human malaria
• The red cell membranes express new adhesive
  protein and adhere to the endothelial cell
• red cell obstruction of the microcirculation in
  addition to hemolysis may be responsible for
  acute life-threatening symptoms.

Black water fever hemoglobinuria due to massive
intravascular hemolysis can occur
Cerebral malaria with focal and generalized
convulsions
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Chemoprophylaxis

• Travelers should be
• Advised to start chemoprophylaxis before travel
  and to use prophylaxis continuously while in
  malaria-endemic areas and for 4 weeks
  (chloroquine, doxycycline, or mefloquine) or 7
  days (atovaquone/proguanil or primaquine) after
  leaving such areas.
• Questioned about drug allergies and other
  contraindications for use of drugs to prevent
  malaria.

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• Advised which drug to use for chemoprophylaxis
  and whether atovaquone/proguanil should be
  carried for presumptive self-treatment.
• Informed that any antimalarial drug can cause
  side effects and, if these side effects are
  serious, that medical help should be sought
  promptly and use of the drug discontinued.
• Advised that, while using chemoprophylaxis
  greatly decreases their risk of acquiring
  malaria, preventive measures cannot guarantee
  complete protection.

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Risk for acquiring drug-resistant P. falciparum
malaria

• The resistance of P. falciparum to chloroquine
  has been confirmed in all areas with P.
  falciparum malaria except the Dominican Republic,
  Haiti, Central America west of the Panama Canal,
  Egypt, and some countries in the Middle East.
• In addition, resistance to sulfadoxine-pyrimethami
  ne (e.g., Fansidar) is widespread in the Amazon
  River Basin area of South America, much of
  Southeast Asia, other parts of Asia, and,
  increasingly, in large parts of Africa.
• Resistance to mefloquine has been confirmed on
  the borders of Thailand with Burma (Myanmar) and
  Cambodia, in the western provinces of Cambodia,
  and in the eastern states of Burma (Myanmar).

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Malaria-endemic countries in the Western
Hemisphere
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Malaria-endemic countries in the Eastern
Hemisphere
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Repellents

• Permethrin-containing repellents (e.g.,
  Permanone) are recommended for use on clothing,
  shoes, bed nets, and camping
• Permethrin is highly effective both as an
  insecticide and as a repellent.
  Permethrin-treated clothing repels and kills
  ticks, mosquitoes, and other arthropods and
  retains this effect after repeated laundering.

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In Case of Illness

• Travelers should be Informed that symptoms of
  malaria can be mild to severe and that they
  should suspect malaria if they experience fever,
  chills, or other influenza-like symptoms such as
  persistent headaches, muscle aches and weakness,
  vomiting, or diarrhea.
• Informed that malaria can be fatal if treatment
  is delayed. Medical help should be sought
  promptly if malaria is suspected, and a blood
  sample should be taken and examined for malaria
  parasites on one or more occasions.
• Reminded that self-treatment should be taken only
  if prompt medical care is not available and that
  medical advice should still be sought as soon as
  possible after self-treatment.

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Sleeping sickness or African trypanosomiasis

• is a parasitic disease in people and animals,
  caused by protozoa of genus Trypanosoma and
  transmitted by the tsetse fly. The disease is
  endemic in certain regions of Sub-Saharan Africa,
  covering about 36 countries and 60 million
  people. It is estimated that 50,000 to 70,000
  people are currently infected, the number having
  declined somewhat in recent years.1 Three major
  epidemics have occurred in the past hundred
  years, one between 1896 - 1906, and the other two
  in 1920, 1970.

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• The disease is found in two forms, depending on
  the parasite, either Trypanosoma brucei gambiense
  or Trypanosoma brucei rhodesiense.
• T. b. gambiense is found in central and western
  Africa it causes a chronic condition that can
  extend in a passive phase for months or years
  before symptoms emerge.
• T. b. rhodesiense, is the acute form of the
  disease but has a much more limited range. It is
  found in southern and eastern Africa its
  infection emerges in a few weeks and is more
  virulent and faster developing

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• Humans are the main reservoir for Trypanosoma
  brucei gambiense, but this species can also be
  found in pigs and other animals.
• Wild game animals and cattle are the main
  reservoir of T. b. rhodesiense.

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• Over 60 million people living in some 250 foci
  are at risk of contracting the disease,
• There are about 300,000 new cases each year.
• The disease has been recorded as occurring in 36
  countries, all in sub-Saharan Africa.

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Symptoms

• begin with fever, headaches, and joint pains.
• As the parasites enter through both the blood
  and lymph systems, lymph nodes often swell up to
  tremendous sizes.
• Winterbottom's sign, the telltale swollen lymph
  glands along the back of the neck may appear.
• If untreated, symptoms spread to include anemia,
  endocrine, cardiac, and kidney diseases and
  disorders.
• The disease then enters a neurological phase when
  the parasite passes through the blood-brain
  barrier.

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The symptoms of the second phase

• give the disease its name
• besides confusion and reduced coordination, the
  sleep cycle is disturbed with bouts of fatigue
  punctuated with manic periods progressing to
  daytime slumber and nighttime insomnia. Without
  treatment, the disease is fatal, with progressive
  mental deterioration leading to coma and death.
  Damage caused in the neurological phase can be
  irreversible.

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In addition to the bite of the tsetse fly

• Mother to child infection the trypanosome can
  cross the placenta and infect the fetus, causing
  perinatal death.
• Laboratories accidental infections, for example,
  through the handling of blood of an infected
  person and organ transplantation, although this
  is uncommon.

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LifeCycle
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Treatment

• For first stage is
• Intravenous pentamidine (for T.b. gambiense) or
• Intravenous suramin (for T.b. rhodesiense)
• For second (late ) stage is
• Intravenous melarsoprol 2.2 mg/kg daily for 10
  consecutive days

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Chagas disease (also called American
trypanosomiasis)

• A potentially fatal disease of humans.
• Pathogenic agent is Trypanosoma cruzi, which is
  transmitted to humans and other mammals mostly by
  hematophagous assassin bugs of the subfamily
  Triatominae (Family Reduviidae).
• Two forms
• trypomastigote found in human blood
• and amastigote found in tissues.
• The acute form usually goes unnoticed and may
  present as a localized swelling at the site of
  entry of the parasites in the skin.
• The chronic form may develop 10 to 20 years after
  infection. This form affects internal organs
  (e.g. the heart, esophagus, colon and the
  peripheral nervous system). Affected people may
  die from heart failure.

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• Therapy consists of Nifurtimox and benznidazole
  for acute cases. There is currently no effective
  therapy for chronic cases.
• Those insects are known by numerous common names
  varying by country, including benchuca, vinchuca,
  kissing bug, chipo and barbeiro.
• Other forms of transmission are possible, though,
  such as ingestion of food contaminated with
  parasites, blood transfusion and fetal
  transmission.

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LEISHMANIA
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• Can be transmitted in many tropical and
  sub-tropical countries, and is found in parts of
  about 88 countries.
• Approximately 350 million people live in these
  areas.
• More than 90 percent of the world's cases of
  visceral leishmaniasis are in India, Bangladesh,
  Nepal, Sudan, and Brazil.
• Also found in Mexico, Central America, and South
  Americafrom northern Argentina to southern Texas
  (not in Uruguay, Chile, or Canada), southern
  Europe (leishmaniasis is not common in travelers
  to southern Europe), Asia (not Southeast Asia),
  the Middle East, and Africa (particularly East
  and North Africa, with some cases elsewhere).

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• L.donovani visceral leishmaniasis
• L.braziliensis cutaneous
• L.mexicana
• L.tropica

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Signs and symptoms

• Leishmaniasis is transmitted by the bite of
  female phlebotomine sandflies.
• Skin sores which erupt weeks to months after the
  person affected is bitten by sand flies
• Other consequences, which can become manifest
  anywhere from a few months to years after
  infection, include fever, damage to the spleen
  and liver, and anaemia.

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There are 4 main forms of leishmaniasis

• Visceral leishmaniasis - the most serious form
  and potentially fatal if untreated.
• Cutaneous leishmaniasis - the most common form
  which causes numerous sores on the body, which
  heal within a few months leaving unpleasant
  looking scars.
• Diffuse cutaneous leishmaniasis - this form
  produces widespread skin lesions which resemble
  leprosy and is particularly difficult to treat.
• Mucocutaneous leishmaniasis - commences with skin
  ulcers which spread causing tissue damage to
  (particularly) nose and mouth

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Cutaneous leishmaniasis

• It is a skin infection caused by There are about
  20 species of Leishmania that may cause cutaneous
  leishmaniasis.
• A raised, red lesion develops at the site of the
  bite (often weeks or sometimes years afterwards).
  The lesion then ulcerates and may become
  secondarily infected with bacteria.

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CUTANEOUS LEISHMANIASIS
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• 2. Mucocutaneous leishmaniasis
• it produces destructive and disfiguring lesions
  of the face.

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Visceral leishmaniasis (VL),

• also known as kala-azar and black fever is the
  second-largest parasitic killer in the world
  (after malaria), responsible for an estimated
  half-million deaths worldwide each year
• The parasite migrates to the visceral organs such
  as liver, spleen and bone marrow and if left
  untreated will almost always result in the death
  of the mammalian host.
• Symptoms include fever, weight loss, anaemia and
  substantial swelling of the liver and spleen.
• Of particular concern, according to the World
  Health Organization (WHO), is the emerging
  problem of HIV/VL co-infection.

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3. Kala-Azar
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Post kala-azar dermal leishmaniasis
after full and adequate treatment may then
re-appear as multiple raised skin lesions
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The traditional treatment

• is with pentavalent antimonials such as sodium
  stibogluconate and meglumine antimoniate.
• Resistance is now common in India and the
  treatment of choice for visceral leishmaniasis
  acquired in India is now Amphotericin B in its
  various preparations (Ambisome, Abelcet,
  Amphocil)
• AmBisome dose total dose 21mg/kg
  (Mediterranean/Brazilian VL) total dose 7.5mg/kg
  over 6 days (Indian VL)
• Amphocil dose total dose 7.5mg/kg over 6 days
  (Indian VL)

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Viral Hemorrhagic Fevers

• Viral hemorrhagic fevers (VHFs) refer to a group
  of illnesses that are caused by several distinct
  families of viruses.
• In general, the term "viral hemorrhagic fever" is
  used to describe a severe multisystem syndrome
  (multisystem in that multiple organ systems in
  the body are affected). 
• Characteristically, the overall vascular system
  is damaged, and the body's ability to regulate
  itself is impaired. 
• These symptoms are often accompanied by
  hemorrhage (bleeding)

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VHFs are caused by

• arenaviruses,
• filoviruses,
• bunyaviruses,
• flaviviruses

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Marburg Hemorrhagic Fever

• Marburg virus was first recognized in 1967, when
  outbreaks of hemorrhagic fever occurred
  simultaneously in laboratories in Marburg and
  Frankfurt, Germany and in Belgrade, Yugoslavia
  (now Serbia). A total of 37 people became ill
  they included laboratory workers as well as
  several medical personnel and family members who
  had cared for them. The first people infected had
  been exposed to African green monkeys or their
  tissues. In Marburg, the monkeys had been
  imported for research and to prepare polio
  vaccine.

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Symptoms

• After an incubation period of 5-10 days, the
  onset of the disease is sudden and is marked by
  fever, chills, headache, and myalgia.
• Around the fifth day after the onset of
  symptoms, a maculopapular rash, most prominent on
  the trunk (chest, back, stomach), may occur.
• Nausea, vomiting, chest pain, a sore throat,
  abdominal pain, and diarrhea then may appear.
• Symptoms become increasingly severe and may
  include jaundice, inflammation of the pancreas,
  severe weight loss, delirium, shock, liver
  failure, and multi-organ dysfunction.

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Treatment

• A specific treatment for this disease is unknown.
  
• Sometimes treatment also has used transfusion of
  fresh-frozen plasma and other preparations to
  replace the blood proteins important in clotting.

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The geographic distribution of tropical ulcer

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• The ulcers occur at all ages, being recorded from
  age 5 to 70 years old.
• In children the sex incidence is equal,
• In adults in most countries they are more common
  in men this reflects the higher probability of
  trauma to the male leg.

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• The necrotic ulcers produce epithelial
  hyperplasia which can both clinically and
  histologically simulate squamous cell carcinoma.
• Malignant degeneration occurs in about 2-9 of
  chronic tropical ulcers it is rare before the
  age of 20

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• All start with relatively minor injury to the
  skin
• Small cuts, bruises, abrasions from thorns,
  insect bites, and damage from grasses, stumps,
  and rocks when people walk through long grass are
  common etiological factors.
• The wounds are then contaminated either by flies,
  dirt, or the patient's saliva.
• Because wounds in the tropics are frequently
  dressed with local remedies, which may include
  cow dung, tobacco, or compresses of moss,
  infection is almost inevitable.
• If the wounds are washed routinely with soap and
  water, the incidence of tropical ulcer declines
  sharply.

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Onchocerciasis is the second leading cause of
blindness worldwide, affecting over 18 million
people
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Onchocerciasis endemic areas
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Vektoriks on erinevad mustad kärbsed Hammustades
nakatavad inimest mikroskoopilise microfilariae
vormiga . Inimese organismis areneb 1 nädalaga
infektsioosne larv. Täiskasvanud isased ussid
?5cm pikad, emased kuni 1 meeter. Emane uss
produtseerib ? 10 000 mikrofilaariat
päevas. Emase ussi eluiga on 10 aastat.
female
Male Onchocerca volvulus
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Onchocerciasis leopard skin

• Disease manifestations
• Subcutaneous nodules
• (adult worms often attach to bones
• or joints)
• Skin changes severe
• pruritus and rash,
• maculopustular reaction,
• pigmentary changes, atrophy
• Eye changes microfilaria in cornea, anterior
  chamber and retina uveitis sclerosing
  keratitis chorioretinal atrophy

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• The treatment for onchocerciasis is ivermectin
  (Mectizan) infected people can be treated once
  every twelve months. The drug paralyses the
  microfilariae and prevents them from causing
  itching.