Vírus Chikungunya

Classificação

Características Gerais

Caraterísticas básicas

Vírus Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus:

• Família Togaviridae Togaviridae A family of RNA viruses, mainly arboviruses, consisting of two genera: alphavirus (group A arboviruses), and rubivirus. Virions are spherical, 60-70 nm in diameter, with a lipoprotein envelope tightly applied to the icosahedral nucleocapsid. Rubella Virus
• Género Alphavirus Alphavirus A genus of togaviridae, also known as group a arboviruses, serologically related to each other but not to other togaviridae. The viruses are transmitted by mosquitoes. The type species is the sindbis virus. Equine Encephalitis Viruses
• Genoma:
  • RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure de cadeia simples de sentido positivo
  • Tamanho: 11,8 kb
• Propriedades:
  • Com envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology
  • O envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology de bicamada lipídica possui glicoproteínas codificadas por vírus, que medeiam a ligação e a entrada nas células:
    • E1 E1 An aromatized C18 steroid with a 3-hydroxyl group and a 17-ketone, a major mammalian estrogen. It is converted from androstenedione directly, or from testosterone via estradiol. In humans, it is produced primarily by the cyclic ovaries, placenta, and the adipose tissue of men and postmenopausal women. Noncontraceptive Estrogen and Progestins: consiste em peptídeos de fusão, que se dissociam de E2 em pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance baixo e facilitam a libertação de nucleocapsídeos no citoplasma do hospedeiro
    • E2: liga-se a recetores celulares, o que resulta em endocitose mediada pelos recetores
  • Capsídeo icosaédrico pequeno

Epidemiologia

Distribuição geográfica:

• Surtos frequentes:
  • África
  • Sudeste da Ásia
• Subcontinente indiano
• América do Sul e ilhas das Caraíbas
• Estados Unidos:
  • Casos relatados de turistas que viajam para as áreas acima referidas
  • Transmissão local observada na Florida, Porto Rico e Ilhas Virgens dos Estados Unidos

Patogénese

Vetores

• Mosquitos do género Aedes
• Principais vetores (também transmitem o vírus Zika Zika Zika virus belongs to the genus Flavivirus and is primarily transmitted by Aedes aegypti mosquitoes, but can also be transmitted sexually and transplacentally. Although most infected patients are asymptomatic, some may present with low-grade fever, pruritic rash, and conjunctivitis. Zika Virus Infection e o vírus dengue Dengue An acute febrile disease transmitted by the bite of aedes mosquitoes infected with dengue virus. It is self-limiting and characterized by fever, myalgia, headache, and rash. Severe dengue is a more virulent form of dengue. Dengue Virus):
  • A. aegypti
  • A. albopictus A. albopictus Chikungunya Virus

Reservatórios

• Humanos
• Primatas: O vírus está presente em África e é mantido no ciclo selvagem (por exemplo, primatas selvagens, macacos e mosquitos).

Transmissão

• Transmitida de mosquitos para humanos
• Transmissão vertical (raro)
• Transfusão de sangue (raro)

Fatores de risco do hospedeiro

• Proximidade dos locais de reprodução de mosquitos
• A doença grave pode ocorrer em:
  • Recém-nascidos
  • Adultos ≥ 65 anos de idade
  • Indivíduos com comorbilidades, como diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus ou doença cardiovascular

Fisiopatologia

• O vírus Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus é introduzido na pele humana e na corrente sanguínea através de uma picada de mosquito.
• A replicação viral ocorre nos fibroblastos dérmicos e depois na corrente sanguínea:
  • O vírus invade e replica diretamente nas articulações e nos músculos.
  • ↑ das citocinas pró-inflamatórias e células inflamatórias
• A disseminação e invasão de outros órgãos pode ocorrer:
  • Fígado (células endoteliais)
  • Cérebro (células endoteliais e epiteliais)
  • Tecido linfoide (gânglios linfáticos e baço)
• A doença articular crónica é observada em até 60% dos doentes e causada por:
  • Replicação viral persistente
  • Resposta imune contínua ao RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure remanescente
  • Autoimunidade

Apresentação Clínica

Infeção neonatal

A infeção do recém-nascidos é observada até 1 semana após o parto. Os sinais e sintomas incluem:

• Febre
• Má alimentação
• Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
• Rash Rash Rocky Mountain Spotted Fever
• Trombocitopenia
• Doença neurológica (meningoencefalite)

Infeção de crianças e adultos

O período de incubação é de 3 a 7 dias. Os sintomas da febre Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus aparecem até 1 semana após a infeção e incluem:

• Febre alta
• Artralgia debilitante e artrite:
  • Bilateral e simétrica
  • Poliarticular: geralmente envolve as pequenas articulações das mãos, punhos e tornozelos
  • Os doentes geralmente apresentam-se em postura fletida devido à dor.
  • O desenvolvimento de artrite crónica aumenta naqueles ≥ 45 anos de idade e/ou com osteoartrite preexistente.
• Cefaleia
• Mialgias
• Rash Rash Rocky Mountain Spotted Fever maculopapular Maculopapular Dermatologic Examination (extremidades e tronco)
• Conjuntivite
• Linfadenopatia

Sintomas graves podem ocorrer em pessoas com fatores de risco:

• Encefalite
• Miocardite
• Hepatite
• Insuficiência renal
• Hemorragia

Diagnóstico

Diagnóstico

• História clínica: febre, dor nas articulações e exposição relevante (ou seja, viajar ou morar em área endémica)
• Testes Testes Gonadal Hormones confirmatórios:
  • Serologia via ELISA ELISA An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. St. Louis Encephalitis Virus ou anticorpo fluorescente indireto (IFA, pela sigla em inglês):
    • IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions observada no 5º dia do início dos sintomas e pode persistir até 3 meses
    • IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis observada 2 semanas após o início dos sintomas
  • RT-PCR RT-PCR A variation of the pcr technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard pcr protocols. Polymerase Chain Reaction (PCR) do RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure do vírus Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus
  • Cultura do vírus

Testes Testes Gonadal Hormones adicionais

Como os complexos de sintomas são semelhantes e os doentes podem estar coinfetados com mais MAIS Androgen Insensitivity Syndrome de 1 vírus, o CDC e a WHO recomendam testar os vírus Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus, Dengue Dengue An acute febrile disease transmitted by the bite of aedes mosquitoes infected with dengue virus. It is self-limiting and characterized by fever, myalgia, headache, and rash. Severe dengue is a more virulent form of dengue. Dengue Virus e Zika Zika Zika virus belongs to the genus Flavivirus and is primarily transmitted by Aedes aegypti mosquitoes, but can also be transmitted sexually and transplacentally. Although most infected patients are asymptomatic, some may present with low-grade fever, pruritic rash, and conjunctivitis. Zika Virus Infection em doentes que apresentam sintomas suspeitos.

Hemograma:

• Linfopenia
• Trombocitopenia

Outros achados:

• ↑ Transaminases Transaminases A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. Autoimmune Hepatitis hepáticas
• ↑ Creatinina

Tratamento

Doença aguda

O tratamento da febre Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus é sintomático:

• Analgesia Analgesia Methods of pain relief that may be used with or in place of analgesics. Anesthesiology: History and Basic Concepts:
  • Acetaminofeno para dor e febre
  • Evitar AINEs e aspirina até febre dengue Dengue An acute febrile disease transmitted by the bite of aedes mosquitoes infected with dengue virus. It is self-limiting and characterized by fever, myalgia, headache, and rash. Severe dengue is a more virulent form of dengue. Dengue Virus estar excluída (devido ao risco de hemorragia)
• Hidratação

O rash Rash Rocky Mountain Spotted Fever desaparece espontaneamente e os sintomas geralmente melhoram em 1 mês.

Doença pós-aguda

• Os sintomas podem persistir ou recidivar, especialmente dor nas articulações.
• Analgésicos como acetaminofeno e/ou AINEs podem ser usados.
• Para sinovite grave e elevação contínua de marcadores inflamatórios, pode ser administrado um esquema curto de glucocorticoides.
• Para sintomas ≥ 3 meses, podem ser administrados fármacos antirreumáticos modificadores da doença ( DMARDs DMARDs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs), pela sigla em inglês), como metotrexato e sulfassalazina.

Prevenção

Evitar áreas de reprodução de mosquitos atarvés de controlo ambiental (ou seja, sem água parada em recipientes) e usar proteção individual:

• Repelente de insetos
• Usar roupas de proteção.
• Dormir debaixo de uma rede de mosquitos.

Comparações de Espécies

O vírus Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus e o vírus da Encefalite Equina pertencem ao género Alphavirus Alphavirus A genus of togaviridae, also known as group a arboviruses, serologically related to each other but not to other togaviridae. The viruses are transmitted by mosquitoes. The type species is the sindbis virus. Equine Encephalitis Viruses e são as principais etiologias de encefalite nos Estados Unidos.

Diagnóstico Diferencial

Condições que mimetizam a febre Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus aguda, têm um complexo de sintomas semelhante e pertencem à família Flaviridae e ao género Flavivirus Flavivirus A genus of flaviviridae containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is yellow fever virus. Tick-borne Encephalitis Virus:

• Vírus dengue Dengue An acute febrile disease transmitted by the bite of aedes mosquitoes infected with dengue virus. It is self-limiting and characterized by fever, myalgia, headache, and rash. Severe dengue is a more virulent form of dengue. Dengue Virus: pequeno vírus de RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure cadeia simples, de sentido positivo, transmitido aos humanos pela picada de uma fêmea do mosquito Aedes. A maioria das infeções é assintomática. Indivíduos sintomáticos podem progredir por diferentes estadios. A fase febril inclui febre, cefaleia, dor retro-orbitária, mialgias, artralgias e rash Rash Rocky Mountain Spotted Fever maculopapular Maculopapular Dermatologic Examination. Manifestações mais MAIS Androgen Insensitivity Syndrome graves de extravasamento capilar, hemorragia e choque podem ocorrer na fase crítica. A resolução dos sinais e sintomas ocorre na fase de convalescença. Os testes Testes Gonadal Hormones de diagnóstico incluem serologia, teste de antigénio ou PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR). O tratamento é de suporte.
• Vírus Zika Zika Zika virus belongs to the genus Flavivirus and is primarily transmitted by Aedes aegypti mosquitoes, but can also be transmitted sexually and transplacentally. Although most infected patients are asymptomatic, some may present with low-grade fever, pruritic rash, and conjunctivitis. Zika Virus Infection: vírus de RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure cadeia simples, de sentido positivo mais MAIS Androgen Insensitivity Syndrome frequentemente transmitido por um mosquito A. aegypti. O vírus pode também ser transmitido sexualmente e por via transplacentária. A maioria dos doentes infetados está assintomática, mas alguns podem apresentar febre baixa, rash Rash Rocky Mountain Spotted Fever pruriginoso e conjuntivite. A síndrome congénita Zika Zika Zika virus belongs to the genus Flavivirus and is primarily transmitted by Aedes aegypti mosquitoes, but can also be transmitted sexually and transplacentally. Although most infected patients are asymptomatic, some may present with low-grade fever, pruritic rash, and conjunctivitis. Zika Virus Infection é uma infeção fetal transplacentária, que se manifesta com defeitos oculares, microcefalia, espasticidade e convulsões. O diagnóstico é feito por RT-PCR RT-PCR A variation of the pcr technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard pcr protocols. Polymerase Chain Reaction (PCR) ou serologia. O tratamento é principalmente de suporte. A prevenção inclui o controlo da população de mosquitos com repelente de insetos e roupas de proteção.

Condições que se apresentam como artrite crónica:

• Artrite reumatoide soronegativa: artrite inflamatória em 3 ou mais MAIS Androgen Insensitivity Syndrome articulações, que dura por > 6 semanas. Os testes Testes Gonadal Hormones de fator reumatoide e antipeptídeo citrulinado cíclico são negativos e podem apresentar-se de forma semelhante à infeção por Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus. A serologia e a história (incluindo viagens) distinguem a artrite reumatoide soronegativa da infeção por Chikungunya Chikungunya Chikungunya virus belongs to the Alphavirus genus and causes a viral infection characterized by fever and joint pain. Symptoms usually appear within 1 week of infection. Additional manifestations of chikungunya virus may include muscle pain, headache, maculopapular rash, and lymphadenopathy. Chikungunya Virus.
• Artrite reativa: artrite que ocorre concomitantemente com ou após uma infeção extra-articular. As características incluem oligoartrite assimétrica (muitas vezes envolve as extremidades inferiores), entesite, dor nas costas e dactilite. O diagnóstico é feito pela história (é frequentemente observada infeção gastrointestinal ou urinária) e após exclusão de outras etiologias de artrite com exames laboratoriais e de imagem.