The severity of infection varies dramatically from one species to. Pdf molecular mechanisms of varicella zoster virus. In sharp contrast to smallpox, infection results in a mild, localized skin disease that presents as small, raised, pearly looking lesions called mollusca. Parapox and molluscum infections are relatively painless and cause. Varicella zoster virus vzv is a neurotropic alpha herpes virus and the causative agent of varicella. Pdf members of the family poxviridae form a large group of viruses that can infect. That is, mice vaccinated against mousepox resisted infection with the usual mousepox virus but contracted the fatal disease when they were given a mousepox. The virus replicates in the cytoplasm of cells of the. Generally associated with normal aging andtewith anything that causes reduced immunocompetence. He concluded that the secondary cases of chickenpox which developed did so because of airborne spread of virus. Poxviruses are a highly successful family of pathogens, with variola virus, the causative. Nov 08, 2019 poxviruses members of the poxviridae family can infect both humans and animals.
Today, poxvirus diagnostics covers the entire spectrum of either traditional. Primary infection causes varicella chickenpox, after which virus becomes latent in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia along the entire neuraxis. Pathogenesis and current approaches to control of varicella. For reasons that are not fully known, the virus can reactivate years later causing shingles. Chickenpox is a very contagious disease caused by the varicella zoster virus and spreads easily from people mainly by touching or breathing in the virus particles that come from chickenpox blisters, and possibly through tiny droplets from infected.
A role for zdna binding in vaccinia virus pathogenesis pnas. A highly fatal, flat hemorrhagic form of goat pox, with papules that seem to coalesce over the body, has been reported in european breeds of goats. A cowpox virus gene required for multiplication in chinese hamster ovary cells. The morbidity and mortality due to the primary and secondary diseases that vzv causes, varicella and herpes zoster hz, are significant. Immune response is the constellation of mechanisms by which the host limits continued multiplication of the pathogen. Investigating vzv pathogenesis is challenging as vzv is a humanspecific virus. While some poxviruses, such as smallpox variola virus, no longer exist in nature, other poxviruses can still cause disease. A primary viremia occurs 4 to 6 days after infection and disseminates the virus to other organs, such as the liver, spleen, and sensory ganglia. There are currently 69 species in this family, divided among 28 genera, which are divided into two subfamilies. Poxviruses are unique among animal viruses in several respects.
Although varicella zoster virus may play a role in the pathogenesis of giant cell arteritis gca, research suggesting that reactivation of the varicella zoster virus is an infectious trigger of gca has been difficult to replicate. Varicella zoster virus vzv infection provides a valuable model for investigating cellcell fusion because of the importance of this process for pathogenesis in human skin and sensory ganglia. Volepox virus pathogenesis in california mice peromyscus californicus. Yatapoxviruses include tanapox virus and yabapoxviruses. Smallpox may be identified via growth of chicken embryo and examination of pock lesions under specific temperatures.
Mechanisms of varicella pathogenesis messaoudi lab. Varicella zoster virus vzv virology and pathogenesis. Smallpox is created from the virus variola which inoculates itself. Viral disease is a sum of the effects on the host of virus replication and of the immune response. Varicella zoster virus vzv is the causative agent of varicella chickenpox and zoster shingles. Because the mode of transmission of vzv is primarily respiratory aerosol, there is a high.
In addition, pcr analysis may allow for a definite determination. Whitley, in mandell, douglas, and bennetts principles and practice of infectious diseases eighth edition, 2015. Because their pathogenesis andpathophysiology are better understood than in many virus infections, and because very striking rashes are produced, rickettsial diseases will also be considered. In addition, virus replication is apparently correlated with the severity of clinical disease, i. These mechanisms include t cell and b cell responses that are. Hepatitis b virus structure, symptoms, diagnosis, treatment. Diseases associated with this family include smallpox.
Smallpox infectious diseases merck manuals professional. Poxviruses members of the poxviridae family can infect both humans and animals. Estimated 500,000 1 million cases of zoster diagnosed annually in the u. Nov 30, 2018 the virus enters through the respiratory system conjunctival or upper respiratory mucosa and colonizes the upper respiratory tract.
Aug 15, 2019 hepatitis b virus structure, epidemiology, symptoms, pathogenesis, diagnosis, treatment and vaccines. Like smallpox, monkeypox virus replicates in lymphoid tissue, although it has a greater degree of lymphadenopathy. In primary infection, the varicella virus invades the. Egyptian mummies dating from as early as 1500 bc showed characteristic pox like skin lesions suggestive of smallpox. Varicella zoster virus centers for disease control and.
For instance, there is still noexplanation for the basic difference in distribution ofthe rashes ofchickenpoxandsmallpox, and it is not known whether. Varicella zoster virus vzv causes either chickenpox or shingles. Primary varicella infection chickenpox is considered to be an endemic disease, meaning it occurs at a constant but relatively high rate in a particular population 3. Here the properties of the yatapoxvirus genus are described. The virus first localizes in mononuclear phagocytic cells, is released into the bloodstream, and then localizes again in skin cells. Clinical features of smallpox the term pathogenesis is used to describe the mechanisms involved in the production of disease, from the spread of infection through the body to the molecular and physiological responses of host cells to a pathogen. Smallpox is a highly contagious disease caused by the smallpox virus, an orthopoxvirus. Lesions range in size from that of a pinhead to 5 mm in diameter and may occur. Varicella zoster virus vzv was once thought to be a fairly innocuous pathogen.
It is called monkeypox because it was first identified in laboratory monkeys. Treatment is generally supportive and potentially with. Varicella 353 22 varicella is an acute infectious disease caused by varicella zoster virus vzv. Pathogenesis and pathology smallpox was eradicated in 1980 by the center for disease and control. Vzv is certainly transmissible through the airborne route and does not require close personal contact. Chickenpox occurs in susceptible persons who are exposed to virus after close personal contact.
It is now contained in five labs in the united states and russia, however there are other labs in the world with smallpox. The pathogenesis, pathology and immunology of smallpox and vaccinia contents introduction the portal of entry of variola virus the respiratory tract inoculation smallpox the conjunctiva congenital infection mousepox rabbitpox monkeypox variola virus infection in nonhuman primates smallpox in human subjects. Information on the mode of spread of varicella virus and the development of chickenpox is scanty. The risk of death following contracting the disease was about 30%, with higher rates among babies. Pdf complete coding sequences of the rabbitpox virus genome. For more detailed information, please refer to the pathogenesis section of smallpox virus. Monkeypox virus, which also causes severe disease in humans, is. Investigating vzv pathogenesis is challenging as vzv is a humanspecific virus and infection. The same virus that causes chickenpox also causes shingles herpes zoster. Monkeypox is a viral disease that occurs mostly in central and western africa. Complete coding sequences of the rabbitpox virus genome article pdf available in journal of general virology 86pt 11. What is the pathophysiology of varicellazoster virus vzv. As noted in the text, camelpox is the virus most closely related to variola, the agent of smallpox. Get a printable copy pdf file of the complete article 11m, or click on a page image.
Smallpox initially was introduced to the native populations of the western hemisphere by explorers from europe and later by african slaves. A contribution of vtnfrs to poxvirus pathogenesis has been shown by. Other descriptions of sheep and goat pox mention typical pox like lesions and nodules in the same animal. The term pathogenesis is used to describe the mechanisms involved in the production of disease, from the spread of infection through the body to the molecular and physiological responses of host cells to a pathogen. New information about the mechanisms of varicella zoster virus vzv pathogenesis and the host response to the v i r us has improved our understanding of the threat that vzv reactivation may pose after hematopoietic cell transplantation hct.
Viral pathogenesis this lecture will define and discuss the basic principles of viral pathogenesis, the entire process by which viruses cause disease. Whereas the human variola virus and mouse ectromelia virus encode. Thomson 1916 exposed susceptible children to patients with typical chickenpox in an open ward without there being direct or intermediate contact. Hepatitis b is a viral infection that attacks the liver and can cause both acute and chronic disease. Pdf molecular mechanisms of varicella zoster virus pathogenesis. Poxviruses are transmitted between individuals by several routes. A factor influencing cowpox virus lesion pathogenesis. From the departments of dermatology and microbiology, the university of texas medical branch, galveston, texas. Functionsoftheuniquenterminalregionofglycoproteine in the. Varicella is common and highly contagious and affects nearly all susceptible children before adolescence. Poxvirus infection symptoms, diagnosis and treatment bmj best. In fact, the virus has kept almost a 100% rate of consistent prevalence from generation to generation 1. Poxvirus infections typically result in the formation of lesions, skin nodules, or disseminated rash.
Varicella zoster virus vzv is an exclusively human neurotropic alphaherpesvirus. It manifests as solitary or multiple, 2 to 8mm, domeshaped, pearly, centrally umbilicated papules that may cluster, become more keratotic with trauma, and simulate condyloma acuminata. Newly developed approaches for studying pathogenesis of varicella zoster virus benjamin silver, vivianna lin and hua zhu department of microbiology and molecular genetics, umndjnew jersey medical school, newark, nj, usa journal of. Histopathologic findings in human vzv infections, whether chickenpox or herpes zoster, are virtually identical.
The recurrent infection herpes zoster, also known as shingles has been recognized since ancient times. Viral replication takes place in regional lymph nodes over the next 24 days. Chickenpox is a very contagious disease caused by the varicella zoster virus. First, owing to the cytoplasmic site of virus replication, the virus encodes many enzymes required either for macromolecular precursor pool regulation or for biosynthetic processes. Poxvirus definition is any of a family poxviridae of brickshaped or ovoid doublestranded dna viruses that have a surface lipoprotein membrane covered with tubular or globular structures and that include the vaccinia virus and the causative agents of cowpox, myxomatosis of rabbits, and smallpox. It begins as a blisterlike rash that originates on the face and trunk. Can occur years or even decades after illness with chickenpox. Infection in swine pathogenesis swpv causes generalized cutaneous disease typical of classic pox diseases. Newly developed approaches for studying pathogenesis of.
The main concern for outbreaks is from bioterrorism. The pathogenesis depends on both the virus isolate and the host. Pubmed besser j et al,differential requirement for cell fusion and virion formation in the pathogenesis of varicella zoster virus infection in skin and t cells,2004, j. Varicella zoster virus vzv, an alphaherpesvirus that causes chicken pox varicella and shingles herpes zoster, is a medically important pathogen that causes considerable morbidity and, on occasion, mortality in immunocompromised patients. Following primary infection, vzv establishes latency in the sensory ganglia from which it can reactivate resulting in herpes zoster, a potentially debilitating disease that affects the elderly. Clinical presentation starts by the appearance of a single or multiple, small, pearly white, discrete. Smallpox is classified as a class 2 pathogen due to the strong response of host cells in the setting of normal host immune responses and the more severe damage in host cells with a weaker immune response such as in children and pregnant women 5 6. The parapoxviruses include orf virus, bovine papular stomatitis virus, pseudocowpox virus, deerpox virus, and sealpox virus. Pathogenesis and current approaches to control of varicellazoster virus infections anne a. The virus is believed to replicate at the site of entry in the nasopharynx and in regional lymph nodes. Fortunately, modern advances, including an available vaccine to prevent varicella, a therapeutic vaccine to diminish the incidence and ameliorate.
Varicella zoster virus virology online microbiology notes. The smallpox virus would be classified as a class 2 pathogen according to the damage response framework classification system 5. Varicellazoster virus vzv was once thought to be a fairly innocuous pathogen. When other zdnabinding domains are substituted for the similar e3l domain, the virus retains its lethality after intracranial inoculation. Grace jt jr 1963 the pathogenesis of yaba virusinduced histiocytomas in primates. After a person recovers from chickenpox, the virus stays in the body in an inactive state. Poxvirus infection an overview sciencedirect topics. Varicella, commonly known in the united states as chickenpox, is caused by the varicella zoster virus.
Jun 10, 2003 the nterminal domain of the e3l protein of vaccinia virus has sequence similarity to a family of zdna binding proteins of defined threedimensional structure and it is necessary for pathogenicity in mice. Poxviridae four genera of poxviruses may infect humans. Comparative biochemical and functional analysis of viral and. Clinical features of smallpox the national academies press. Little is known about the route and the source of transmission of the virus. Investigating vzv pathogenesis is challenging as vzv is a humanspecific virus and infection does not occur, or is highly restricted, in other species. Pdf immune response to poxvirus infections in various animals. Vzv pathogenesis charles grose vzv virology laboratory. It can affects both children and adults through direct contact or indirectly via fomites, swimming pools and towels in addition to the sexual transmission which can occurs in adults 2. Pathogenesis and current approaches to control of varicella zoster virus infections.
The last naturally occurring case was diagnosed in october 1977, and the world health organization who certified the global eradication of the disease in 1980. Poxviruses are a highly successful family of pathogens, with variola virus, the causative agent of smallpox, being the most notable member. Smallpox likely originated in egypt or india more than 3,000 years ago who. The disease is generally regarded as a mild, selflimiting viral illness with occasional complications. Differentiation of smallpox virus from varicella, vaccinia, cowpox and herpes viruses. Original article pathogenesis of molluscum contagiosum. Chickenpox has an incubation period of 1021 days and is. Sheep pox and goat pox are endemic in africa north of the equator, the middle east and asia, while some parts of europe have experienced outbreaks recently.
The orthopoxviruses include smallpox variola, monkeypox, vaccinia, cowpox, buffalopox, cantagalo, and aracatuba viruses. Mucosal lesions can develop at various sites including. Molluscum contagiosum is caused by another exclusively human poxvirus molluscum contagiosum virus. Molluscum contagiosum is caused by a large poxvirus molluscum contagiosum virus, which is a doublestranded, brickshaped dna virus. Infection in humans usually occurs due to contact with contaminated animals, people, or materials. Smallpox was an infectious disease caused by one of two virus variants, variola major and variola minor. Varicella zoster virus not associated with giant cell. Various animal models have been developed to study the pathogenesis of poxvirus infections. Arvin2 departments of pediatrics and microbiology and immunology, stanford university school of medicine, stanford, ca 94305. Sheeppox virus sppv and goatpox virus gtpv are the causative agents of sheep pox and goat pox, and with lumpy skin disease virus make up the genus capripoxvirus in the family poxviridae. Molecular mechanisms of varicella zoster virus pathogenesis.
Varicellazoster virus vzv, an alphaherpesvirus that causes chicken pox varicella and shingles herpes zoster, is a medically important pathogen that causes considerable morbidity and, on occasion, mortality in immunocompromised patients. However, it is much more common among animals such as rats, mice, rabbits, and the african squirrel. Chickenpox is an infection caused by the varicella zoster virus. When smallpox was being eradicated worldwide, the world health organization who. Laboratory diagnosis of smallpox and similar viral diseases by means of tissue culture methods. Herpes zoster can afflict the elderly with a debilitating condition, postherpetic neuralgia, triggering severe, untreatable pain for months or years. Variola major virus smallpox virus, variola minor virus alastrim, and monkeypox virus are classified as select agents select agents and therefore are regulated under 42 cfr part 73 possession, use, and transfer of select agents and toxins, which was published in final form in the federal register in march 2005 and amended in october 2012. Humans, vertebrates, and arthropods serve as natural hosts. Primary varicella infection chickenpox was not reliably distinguished from smallpox until the end of the 19th century. Vzv spreads from person to person by aerosolizing from skin lesions.
316 926 840 1254 972 281 1236 311 93 1464 504 814 1578 798 985 991 1540 1020 363 1203 925 994 1634 456 115 647 416 1176 651 25 1150 280 395 1228 109 1159 727 54 827 908 553 54 211