Searching for microbes Part XII Virology Part Two

Searching for microbes Part XII. Virology – Part Two Ondřej Zahradníček To practical of a. VLLM 0421 c and a. ZLLM 0421 c zahradnicek@fnusa. cz

Content of this slideshow Story Viruses of measles, mumps and rubella Viruses of influenza More respiratory viruses Mycoplasmas Virus of tick-borne encephalitis Some viral properties important for diagnostics Survey of virology diagnostics Microscopy in virology. Viral isolation Indirect diagnostics of viruses Check-up questions

Story • Mr. Lungman was already a week in a hospital because of long term respiratory problems. A group of medical students started to examine him, but they found no pathological finding. • But then a student, Miss Diligentous spoke: „Patient has a dry cough, physical examination showed nothing. What about an atypical pneumonia? “ The teacher smiled: Excellent, I am glad that someone found it!

Atypical pneumoniae • Classifying pneumoniae as “classical“ and “atypical“ is recently disputed, nevertheless, it is still used for pneumoniae that – have a slow oncome, rather non-productive cough, and physical symptomatology is often absent (but x-rays show a visible finding) – are not caused by culturable bacteria (e. g. Streptococcus pneumoniae) – The changes are in the interstitium rather than lung vaults – are mostly caused by: • respiratory viruses (see further) • atypical bacteria, (Mycoplasma pneumoniae, or Chlamydia/Chlamydophila pneumoniae, Legionella sp. • In case of bacterial agents, antibiotic therapy (doxycyklin, macrolides) is possible

The viruses described in this slideshow: • viruses of rubella, mumps and measles • respiratory viruses – influenzavirus A and B – parainfluenzavirus – RS viruses – adenoviruses – Mycoplasma pneumoniae – not a virus, but diagnosed using virology methods • virus of tick-borne encephalitis

Measles Mumps Rubella

Measles, mumps and rubella • Although they are not related, one is common for them: vaccination. Living attenutated vaccines is used against all of them. Usually they are vaccinated together as the “MMR trivaccine“ • All of them cause childhood diseases; some people believe that they are not serious and hesitate to let their children vaccinated. Nevertheless, they might have serious complications and kill people • Rubella virus belongs to the Togaviridae family, measles and mumps viruses are members of Paramyxoviridae

A fresh (2017) news from media

Togaviridae • They are RNA enveloped viruses. They are the simplest animal enveloped viruses. They are small (60– 70 nm). Coat (toga in Latin) is made of cell lipids, viral glycoproteins are prominent • This family contains genus Alphavirus, that is arthropod borne (so they are arboviruses): American viruses of equine encephalitis, African chikungunya and o‘nyong viruses • The most important for humans is Rubivirus – rubella virus

Rubivirus (virus of rubella/rubeola) • Virus of measles (rubeo = I am glowing red) is a purely human virus • Measles are a benign childhood disease. Transmission by air, incubation 16– 18 days, virus starts to be excreted by nasopharynx even before the rash. Dangerous is the disease in pregnant women, especially in the first trimester there is a risk of inborn defects – malformations of the hearth, hearing or other organs. Nevertheless, it is also possible that the child is born completely healthy

Diagnostics, prevention, treatment • Diagnostics is usually not needed, clinical examination is sufficient • The virus is multiplied on the cell cultures, but there is no CPE. Multiplication of the virus can be checked by an interference – if there is a rubivirus on the culture, the echovirus 11 (for example), that would perform a cytopathic effect, cannot multiply • Indirect diagnostics is possible by HIT, VNT and ELISA. Avidity of antibodies is checked • Treatment is symptomatic

Virus of rubella http: //vietsciences. free. fr/khaocuu/ng uyenlandung/virus 01. htm

Rubella http: //www. vaccineinformation. org/photos/rubeiac 002. jpg

Paramyxoviridae • This family comprises many RNA enveloped viruses important for humans: • Subfamily Paramyxovirinae – Respirovirus – virus of parainfluenza 1 and 3 – Morbillivirus – virus of measles – Rubulavirus – virus of mumps, viruses of parainfluenza 2, 4 a, 4 b • Subfamily pneumovirinae – Pneumovirus – human RS virus – Metapneumovirus – human metapneumovirus

Mumps virus • Mumps are a generalised infection, that comes from the respiratory mucosa to the whole organism. It does not always attack salivary glands, but is uses to do it. It may also attack pancreas, milk gland testicles, that is why measles are dangerous in man after pubescence. They are also important for pregnant women • Diagnostics contains HIT, CFT, ELISA or viral isolation • Treatment is only symptomatic

Mumps virus http: //vietsciences. free. fr/khaocuu/nguyenlandung/virus 01. htm

Mumps http: //toolbox. esu 16. k 12. ne. us/oscience/Physiology/Projects/Josh. M. htm

Mumps http: //childrensspecialists. com/body. cfm? id=105 6 http: //toolbox. esu 16. k 12. ne. us/oscience/Physiolo gy/Projects/Josh. M. htm

Three in one http: //www. cartoonstock. com/directory/r/rubella_gifts. asp

Measles virus • Unlike majority of other viral diseases, there are no asymptomatic infections in measles. After 10– 11 days of incubation the fever, rhinitis, cough, conjunctivitis is started, and late a characteristic rash that starts on the faces and behind the ears, after 3– 4 days it disappears. In the mouth we can see Koplik spots. • Reactivation in adults may rarely have a form of a subacute sklerotising panencephalitis (SSPE) • Diagnostics ELISA, CFT, HIT

Measles virus http: //vietsciences. free. fr/khaocuu/nguyenlandung/virus 01. htm

Measles http: //www. nytimes. com/imagepage s/2006/04/30/world/20060430_MEAS LES_GRAPHIC. 2. html

Measles (Koplik spots on the right) http: //www. bact. wisc. edu/themicrobialw orld/Viral. Disease. html

Measles www. lib. uiowa. edu/hardin/md/measles. html. http: //z. about. com/d/pediatrics/1/0/e/2/measles. j pg

Measles in short www. gypsy-traveller. org/health/measles. htm.

The more vaccination, the less measles http: //www. who. int/i mmunization_monito ring/diseases/measle s/en/index. html

Viruses of influenza

Influenza (flu) • It is a disease of the whole body, but mostly lower respiratory ways. Neither rhinitis, nor sore throat belongs to typical course. Rather dry cough, high fever, myalgia, acute oncome. Sometimes also intestinal problem may occur. • Influenza is often dangerous in immunocompromissed persons (mostly prolonged), pregnant, in elderly. On the other hand, some subtypes are rather dangerous for young people with very good immunity. This is because of „cytokine storms“ (the problems are related with immunity overreaction) • Influenza A, B and C exist; majority of epidemics is caused by virus of influenza A

Influenzavirus A http: //micro. magnet. fsu. edu/cells/viruses/influenzavirus. html

Influenzavirus A – antigens • Among characteristics of influenzavirus, the most important is antigenic variability. In influenzavirus, we have 15 subtypes according to haemaglutinin antigen (H) and 9 subtypes according to neuraminidase (N). • An antigenic drift is a natural mutation in antigenic structure coding genes of a know type of a virus. It does not bring a completely new virus type • An antigenic exchange – shift means a reassortment of two or more types of a virus (e. g. avian + human) to a new type. Shift only exists in influenza A, as the other types are purely human • Antigenic shift is enabled by segmented genome

Influenza virus gustavorinaldi. blog. lastampa. it

Influenza pandemics • As viruses change, sometimes a new variant occurs and nobody is protected against it. Such a virus is then able to produce outbreaks, epidemics or even pandemics in large areas. Of course, it is never possible to predict the course of them. • Viruses able to perform an outbreak in human population should have not only elevated virulence, but also the ability to be transmitted person-to-person. Bird viruses rarely have such ability. Hogs usually serve as „mixing jar“. So virulence factors from birds usually become dangerous after reassortment or recombination with parts of mammal viruses.

Influenza pandemics 2 • During World War One many people died because of so called Spanish influenza • During following decades, there were many relatively smaller epidemics (Hong-Kong flu, Singapore flu) • The last epidemics („swine influenza“) was caused by a virus belonging to group A: H 1 N 1. The mere term „A: H 1 N 1“ does not mean anything new, but the detail structure was special, the virus contained parts that are human, avian and swine origin

Influenza – prevention, prophylaxis, treatment • Prevention possible by vaccination, recommended mostly to diseased persons. It protects only against subtypes actually present in population, not against new viral subtypes • For prophylaxis and treatment, we can use some antivirotics: inhibitors of protein M 2 (amantadin and rimantadin, some strains became resistant already), and inhibitors of neuraminidase (zanamivir and oseltamivir – factory names TAMIFLU and RELENZA). • Antivirotics should be used for relevant reasons only. Using them „preventively“ because of panic might lead to development to resistance.

Influenzavirus www. ontariogenomics. ca/education/episode 6. asp http: //www. bio-pro. de/en/region/rhein/magazin/01112/index. html

Influenzavirus – life cycle http: //www. accessexcellence. org/RC/VL/GG/influenza. php

In flew Enza From book „A practical guide to clinical bacteriology“, Pattison JR et al. , Wiley, London 1995

More respiratory viruses

Parainfluenzaviruses • They are paramyxoviruses, related with mumps virus and less related with measles • Unlike the true flu they often cause cathars of upper respiratory ways. Nevertheless, flu-like cough may be too, but mostly (especially in adults) without fever. • Diagnostics: CFT, HIT, ELISA; there are some cross-reactions. A direct diagnostics in nasopharynx using isolation on cell cultures possible, too.

RS virus (respiratory syncytia virus, pneumovirus) • Related (not very closely) to parainfluenza • RS-virus is an important pathogen of lower respiratory ways in first half of year • As the name says, they cause confluence of infected cells (syncytia) • Diagnostics – ELISA, direct dg. – cell cultures • Metapneumovirus is a newer virus related to pneumovirus

Adenoviruses – Uncoated DNA viruses • First isolated 1953 from an adenoid vegetation • They are human, animal and bird viruses • They are medium sized (80 nm), uncoated, with cubic symmetry of capsid. They have shape of a perfectly regular icosahedra. The capsid is composed of 240 hexons a 12 top pentons. • We know 47 serotypes of adenoviruses, that can be pathogenic for humans. They could differ in symptoms and diagnostic.

Adenovirus http: //www. tulane. edu/~dmsander/Big_Virology/BVDNAadeno. html

Human adenoviruses • They may cause common cold, pharyngitis, conjunctivitis (light to serious) • Types 40 and 41 (different also by being unculturable) cause diarrhoea in babies • One type may cause inflammation of urinary bladder with bleeding • Diagnostics is culture (cell cultures) and serological (complementfixation test) • Target therapy is impossible

http: //web. uct. ac. za/depts/mmi/stannard/emimages. html Adenovirus

Adenoviruses http: //www. tulane. edu/~dmsander/Big_Viro logy/BVDNAadeno. html

M o c y l p s a m s a

Mycoplasmas http: //www. unmc. edu/dept/biochemistry

Mycoplasmas • strange group of bacteria – Mollicutes – „the ones with soft skin" • they have no cell wall • their shape might be oval, round or filamentous • in humans, genera Mycoplasma and Ureaplasma are important • smallest organisms with no need for an alien cells • several times smaller than common bacteria

www. invivogen. comv www. rowland. harvard. edu

Mycoplasma pneumoniae • causative agent of atypical pneumoniae • sometimes extrapulmonary complications (hearth, nerves etc. ) • on the other hand, often only commoncold-like or asymptomatic • transmission by air

Mycoplasma hominis, Ureaplasma urealyticum • important agents of sexually transmitted diseases • inflammation of vagina and urethra • on the other hand, often present in urethra of healthy persons Other urogenital mycoplasmas: • Mycoplasma genitalium also sexual organs, unclear importance • Mycoplasma penetrans as an opportune infection in AIDS patients

webdb. dmsc. moph. go. th

Mycoplasmas webdb. dmsc. moph. go. th www. newbugs. info

Mycoplasma: diagnostics and treatment • Culture on acellular, nevertheless special media • CFT, ELISA etc. Usually together with serology of respiratory viruses • Not possible to use antibiotics acting against the cell wall • Effective tetracyclines; in children macrolides (i. e. erythromycin etc. ) • In M. pneumoniae vaccination attempts – in stage of experiment

Virus of tick -borne encephalitis

Central European Virus of Tickborne Encephalitis • RNA virus, belongs to flaviviruses • Tick borne encephalitis often infects children, heavy symptoms are mostly in adults. Adults paradoxically rarely let themselves vaccinated. First phase is „flu-like“, second has meningeal or cerebral symptoms. Lethality is 1– 5 %. • It is a typical arbovirus (arthropod borne virus), source of infection are rodents • Diagnostics is mostly indirect diagnostics – CFT, HIT, ELISA. Eventually direct diagnostics virus isolation on newborn mice, eventually PCR

Virus of Tick-borne Encephalitis http: //vietsciences. free. fr/khaocuu/nguyenlandung/virus 01. htm

Some viral properties important for diagnostics

Among viral properties • We know already, that viruses are acellular particles, containing DNA or RNA in a nucleocapsid, and eventually also containing viral envelope • A RBC-agglutinating agent may take part in this envelope. This effect was already seen in J 08 practical in haemaglutination inhibition test. Similar is also ability of haemadsorption • Other properties: Virus needs alien cells. Such cells are found e. g. in a cell culture or in structures of fertilized egg with a chicken embryo

Survey of virology diagnostics

Virology diagnostics • Direct diagnostics – Microscopy: electronoptic, optical only to examination of something, that viruses do in vivo / in vitro (inclusions, cytopathic effect) – Culture isolation Requires living cells. – Biochemical identification is not possible – Animal experiment here equal to isolation – Detection of DNA – in viruses > bacteria – Detection of Ag in specimen – very common • Indirect diagnostics – often more important than direct diagnostics

Influenza – diagnostics • Diagnostics has epidemiologic importance (a proof, that the agent is the true influenza) • Direct influenza diagnostics (sampling: pharyngeal swab in special virology transport medium, or pharynx washing with a special medium) – detection of viral antigen – isolation on amniotic fluid (virus then detected by Hirst test) – isolation on monkey kidney cells – detection of viral RNA using PCR • Indirect influenza diagnostics – classical examination – pair sera, CFT, HIT – ELISA – Ig. M, Ig. A

Microscopy in virology. Viral isolation

Microscopy in virology • Electronoptic microscopy is suitable for observation of majority of viruses, but it is very expensive and not available enough (= not in routine diagnostics) • Optical microscopy may be used – To observe cytopathic effects in vitro (various viruses) – To observe cellular inclusions in vivo (Negri bodies in rabies/lyssa) – rather in histology than microbiology – To observe large viruses (poxviruses) – exceptionally, not for routine diagnostics

Viral isolation • Animal now less commonly. Typical animal is a suckling baby mouse. • Fertilized egg is a classical method: – – Amniotic sac Allantoic sac Yolk sac Chorioallantoic membrane (only here sometimes a visible result – so called pocks; in other cases, the result of egg isolation is not visible) • Cell cultures (cultures of „immortal“ human or animal cells – embryonic or tumour cells): – Examples: LEP, He. La, monkey kidney and various other. Some viruses (only some!) perform a cytopathic effect (CPE) on cell cultures, but some viruses do not.

Fertilized egg and its parts http: //www. kidfarm. net/chicken/embryo. jpg

Another picture of the fertilized egg SH – shell membrane (paper membrane) AB – albumen http: //www. scielo. cl/fbpe/i mg/bres/v 38 n 4/fig 02. gif AM – amniotic sac, YS – yolk sac, AL – allantois CH – chorioallantoic membrane (CAM)

Isolation of viruses etc. on an egg • Amniotic sac, surrounding the embryo, is used often, e. g. in influenza diagnostics • Allantois, used by embryo as cavity for waste, is especially in older embryos easily accessible. It is not very rich in nutrients • Yolk sac is used for chlamydial diagnostics (they are bacteria, but similar to viruses in properties) • Chorioallantoic membrane serves to culture mostly poxviruses and herpesviruses • At production of a vaccine, the virus is cultured on allantois (only possible after several passages in amniotic fluid)

Practical viral agglutination on fertilized egg Ovoscope • In time of technically fantastic machines, understandable for less and less technicians, a nice classical apparatus is ovoscope. The old ovoscope was not suitable because of asbestos, but the new version also has two holes. • One is round to place an egg standing • The second is oval to place an egg laying

Virus application to amniotic sac: how to do it • • • Use ovoscope to see the air membrane Cut the shell next to air membrane Apply alcohol to paper membrane Use your ovoscope again Using needle, try to „stick the eye of the embryo“ (it runs away anyway) • Apply the virus inside • Recap the egg and incubate for several weeks

How can I be sure that a virus is present? • Bacteria at culture form visible colonies, or at least they make the broth turbid. On the other hand, in viral isolation the result is visible only sometimes (CPE, pocks), commonly the result is not visible • Detection of an isolated viruses should be performed • In viruses from amniotic fluid, mostly Hirst test is performed – detection of viral ability to agglutinate erythrocytes • In viruses from cell cultures (e. g. virus of influenza from monkey kidney cells), we use rather test of viral haemadsorption

S = saline V = virus (amniotic fluid) E = erythrocytes 0. 2 0. 2 ml S ml S ----- 0. 2 0. 2 ml V ml ml ml mix, mix, pipette pipette 0. 2 0. 2 ml E ml E to disinfection Hirst test practically

Cytopathic effect (CPE) on cell cultures • Only rarely a cytopathic effect of a virus to a cell makes a change of metabolism, that could be observed as a macroscopically visible colour change after addition of an indicator (as we would see in the virus neutralisation test) • More commonly, CPE can be seen in a microscope: – – the cells become round desmosomic inter-cell connections are lost the cells lose their one-direction orientation globally, chaos replaces the order • Many viruses do not produce any cytopathic effect at all

http: //cmir. mgh. harvard. edu/cellbio/cellculture. php? menu. ID_=122 www. herpesdiagnosis. com/diagnose. html You will see the same picture once again later (HSV is Herpes Simplex virus – HSV 1 causing mostly herpes labialis, HSV 2 herpes genitalis)

Practical observation of cell cultures • Put the entire test tubes to a microscope, trying to focus the inner surface. • Maybe you will see cell cultures, some of them maybe even with a cytopathic effect • An experienced eye recognizes various types of cell cultures, but also various types of eventual cytopathic effects

No CPE present http: //cmir. mgh. harvard. edu/cellbio/cellculture. php? menu. ID_=122 www. herpesdiagnosis. com/diagnose. html (HSV is Herpes Simplex virus – HSV 1 causing mostly herpes labialis, HSV 2 herpes genitalis)

Shell-vials techniques • Those are techniques of quick culture • Inoculum is centrifuged inside of a cell culture growing on a round cover slip • Multiplied virus is detected using immunofluorescence with monoclonal antibodies • During 24 h after material admission everything is done (while classical culture takes several weeks)

Indirect diagnostics of viruses

CFT in respiratory viruses – example • The aim is to found, which of six tested agents is responsible for momentary respiratory problems of our patient • Positive: absence of haemolysis RBC sedimentation to the bottom of the well • Negative: haemolysis („strawberry lemonade“) • Titre = highest serum dilution with still positive reaction • Fourfold increase/decrease of titre is supposed to be significant for running infection when using pair sera

HIT – tick borne encephalitis (example) • Besides CFT, HIT is another classical method to detection of this virus. • Positive: blocation of viral agglutination (= sedimentation of RBCs to the bottom). • Negative: RBC agglutination („potato like“ formation in the well) • Titre = highest serum dilution with still positive reaction • Fourfold increase/decrease of titre is supposed to be significant for running infection when using pair sera

The End http: //www. tulane. edu/~dmsander/Bi g_Virology/BVDNAadeno. html

Check-up questions • 1. How electronoptic and optic microscopy can be used in virology? • 2. What do mean terms „tissue culture“ and „cytopathic effect“? • 3. What sites of inoculation are used in fertilized egg? • 4. Why experimental animals are sometimes used in virology diagnostics? • 5. What specimens and what methods are used in the virology diagnosis of influenza? • 6. What methods for detection of viruses require two specimens and what is the ideal time between taking the first and the second? • 7. Shells-vials techniques: what are they based on? • 8. What are the typical method used for indirect diagnostics of viruses? • 9. What type of organism is Mycoplasma pneumoniae? • 10. What does the abbreviation „RS virus“ mean?