Arbo Map (map by CDC of disease presence such as dengue, west nile). 

Maculopapular Rash Diseases caused by Viruses

Measles (Rubeola): Every year hundreds of thousands of childen in the developing world die from measles, even though an extremely effective vaccine has been available since 1963. 

–Signs and Symptoms: The intial symptoms are sore throat, dry coughing, headache, conjunctivities, lymph adenitis and fever. In a short time, typical oral lesions called Koplik’s spots appear as a prelude to the characteristic red maculopapular exanthem that erupts on the head and then progresses to the trum and extremities until most of the body is covered. The rash gradually coalexes into red patches that fade to brown. 

The most serious complication is subacute sclrosing panencephalitis (SSPe), a progressive neurological generation of the crebral cotrex, white matter, and brain stem. 

Measles implants in the respiratory mucosa and infects the tracheal and bronchial cells. From there, it travels to the lymphatic system, wehre it multiples and then enters the bloodstream, a condition known as viremia. The bloodstream carries the virus to the skin and to various organs. 

The measles virus induces the cell emmbranes of adjacent host cells to fuse into large syncytia, giant cells with many nuclei. These cells no longer perfromt their proper function. 

–Transmission: Measles is one of the most contagious infectious diseases, transmitted principally by respiratory droplets. There is no reservoir other than huans, and a person is infectious during the periods of incubation, prodrom phase, and the skin rash but usually not during convalescence. 

–Vaccination: The MMR vaccine (for measles, mumps and rubella) contains live attenuated measles virus which confers protection for up to 20 years. Measles immunization is recommended for all healthy children at the age of 12-15 months, with a booster before the child enters school. 

Roseola: is common in young children and babies. It can result in a maculopapular rash, but a high percentage of cases proceed without the rash stage. Children exhibit a high fever that comes on quickly and lasts for up to 3 days. On the fourth day, the fever disappears, and it is at this point that a rash can appear, first on the chest and trunk and less prominently on the face and limbs. Roseola is caused by a human herpesvirus called HHV-6. Like all herpesviruses, it can remain latent in its host indefinitely after the disease has cleared. Very occasionally, the virus reactivates in childhood or adulthood, leading to mononucleosis-like or hepatitis-like symptoms. It is thorught that 100% of the US population is infected with this virus by adulthood. Some people experience roseola when they became infection, and some of them did not. No vacine and no treatment exists. 

Rubells (German Measles): causes a relativey minor rash disease with few complications. Two clinical forms of rubella are referred to as postnatal infection, which develops in children or adults and congenital )prenatal) infection of the feturs. Postnatal Rubella presents itself as a rash of pink macules and papules on the face which progresses down the trunk and toward the extremities, advancing and resolving in about 3 days. The rash is milder looking than the measles rash. Adult rubella is often characterized by joint inflammation and pain rather than a rash. 

Vesicular or Pustular Rashes caused by Viral Diseases

Chickenpox: is very common and mostly benign. It has an inucubation period of 10-20 days when the first symptoms to appear are fever and an abundant rash that beings on the scalp, face and trunk and radiates in sparse crops to the extremities. Skin lesions progress quickly from macules and paules to itchy vesicles filled with a clear fluid. In several days, they encrust and drop off, usually healing completely but sometimes leaving a tiny pit or scar. 

About 0.1% of chickenpox cases are follwed by encephalopathy or inflammation of the brain. It can be fatal, but in most cases recovery is complete. 

Human herpesvirus 3 (HHV-3) also called varicella causes both chikenpox and shingles. Like other herpresviruses, it is an enveloped DNA virus. 

Shingles (Herpes Zoster): After recuperation from chickenpox, the virus enters into the sensory nerve endings and cuntaenous spinal nerve branches, especially those that serve the skin of the chest and head. From there, it becomes latent in the ganglia and may reemerge as shingles with its characteristic asymmetrical distribution on the skin of the trunk or head. 

Singles develops abruptly after reactivaiton by such stimuli as pshycholgical stress, x ray treatments, immunosuppresives and other drug therapy, sergery ro a developing malignancy. 

In2006, The FDA approved a unique vaccine called Zostavax. It is intended for adults age 60 and over. 

Smallpox: (see also Bioterrorism) Largely through the WHO global efforts, naturally occurring smallpox is a disease of the past. But it is a bioterrosism disease. Vaccination, which had been discontinued was once again offered to certain US populations. 

Infection begins with fever and malaise and later a rash begins in the pharynx, spreads to the face and prgoresses to the extremities. 

It is important for health care workers to recognize the early signs and symptoms as even a single suspected case must be treated as a health and law enforcement emergency. 

The causative agent of smallpox, the variola virus, is an orthopoxvirus, and enveloped DNA virus. 

In the early 1970s, smallpox was endemic in 31 countries. Every year, 10-15 million people contracted the disease and about 2 milion died form it. 

Affecting the Cardiovascular and Lymphatic System

HIV (see “viruses” and “retrovirsus”

Hemorrhagic Fever Diseases: a number of agents that infect the blood and lymphatics casue extreme fevers, some of which are accompanied by itnernal hemorrhaging. The presence of the virus in the bloodstream casues capillary fragility and disrupts the blood clotting system, which can even lead to death. All of these viruses are RNA enveloped viruses and include the Ebola virus. 

Yellow fever, chikungunya and dengue fever.  Yellow fever, chikungunya and engue are spread by the Aedes genus of mosquito and are common in South Americ and Africa.  In several places in the world trials are being conducted in which male A. aegypti mosquitoes infected with the bacterium Wolbachia are being released in areas with heavy dengue burden. When these males mate with females, the resultant eggs are not delivered. An ebola vaccine which has been shown to be safe and highly effective is also in phase III clinical trials. 

–Eboli Virus: Ebola virus is regarded as the prototype pathogen of viral haemorrhagic fever, causing severe disease and high case-fatality rates. Ebola virus and Marburg virus constitute the family Filoviridae in the order of Mononegavirales. Filoviruses are enveloped, non-segmented, negative-stranded RNA viruses of varying morphology. These viruses have characteristic filamentous particles that give the virus family its name. Ebola haemorrhagic fever is thought to be a classic zoonosis with persistence of the Ebola virus in a reservoir species generally found in endemic areas. Apes, man, and perhaps other mammalian species that are susceptible to Ebola virus infection are regarded as end hosts and not as reservoir species. The different species of Ebola virus seem to cause somewhat different clinical syndromes, but opportunities for close observation of the diseases under good conditions have been rare. Generally, the abrupt onset of Ebola haemorrhagic fever follows an incubation period of 2–21 days (mean 4–10) and is characterised by fever, chills, malaise, and myalgia. The subsequent signs and symptoms indicate multisystem involvement and include systemic (prostration), gastrointestinal (anorexia, nausea, vomiting, abdominal pain, diarrhoea), respiratory (chest pain, shortness of breath, cough, nasal discharge), vascular (conjunctival injection, postural hypotension, oedema), and neurological (headache, confusion, coma) manifestations. Haemorrhagic manifestations arise during the peak of the illness and include petechiae, ecchymoses, uncontrolled oozing from venepuncture sites, mucosal haemorrhages, and post-mortem evidence of visceral haemorrhagic effusions. A macropapular rash associated with varying severity of erythema and desquamate can often be noted by day 5–7 of the illness; this symptom is a valuable differential diagnostic feature and is usually followed by desquamation in survivors. Abdominal pain is sometimes associated with hyperamylasaemia and true pancreatitis. In later stages, shock, convulsions, severe metabolic disturbances, and, in more than half the cases, diffuse coagulopathy supervene. See Feldman

–Chikungunya virus (CHIKV) is an arthropod-borne virus that is transmitted by Aedes (Ae.) mosquitoes. It was first isolated in 1952 in the Makonde Plateau of the southern province of Tanzania (former Tanganyika). The virus transmission cycle requires infection of female mosquitoes via a viraemic bloodmeal taken from a susceptible vertebrate host and, following a suitable extrinsic incubation period, transmission to another vertebrate host during subsequent feeding. After an incubation period, most patients suffer from polyarthralgia and myalgia, with a significant impact on their quality of life. Chikungunya fever is characterised by a very high viraemic load and concomitant abnormalities such as pronounced lymphopenia and moderate thrombocytopenia. The rate of asymptomatic cases is lower, and the percentage of infected patients requiring medical attention is higher, than in most other common arboviral infections. After the acute stage, some patients experienced relapse, persistent arthralgia or musculoskeletal pains. Increase of age is the most obvious risk factor associated with severe disease or persistent symptoms in adults, whilst in paediatric populations, newborns have a higher risk of severe disease. The name “Chikungunya” in the Bantu language of the Makonde people refers to the stooped posture due to the frequent and debilitating joint pain induced during chikungunya fever. The virion has an icosahedral capsid enclosed by a lipid envelope and a diameter of 60–70 nm. It is sensitive to desiccation and to temperatures >58 °C. The genome is a single-stranded, positive sense, RNA molecule of approximately 12 kb in length. See Thimburville

No vaccine exists to prevent chikungunya fever, and there’s no effective antiviral treatment. However, the disease runs a limited course and rarely causes serious complications. Treatment is aimed at relieving symptoms with rest, fluids and medications — such as acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin IB, others) — to relieve joint pain and fever. Chikungunya outbreaks were first reported in Africa, Asia, Europe, and islands in the Indian and Pacific oceans. The first reported case of chikungunya in the Americas occurred in 2013, on islands in the Caribbean. Since then, more than 1.7 million suspected cases of chikungunya have been reported in the Caribbean islands, in Latin American countries and in the United States. Canada and Mexico also have reported cases of infection. See Mayo Clinic.   See WHO

–Yellow Fever: Yellow fever is a viral disease spread to humans, as well as between certain other primates and humans, by the bite of infected mosquitoes. The virus is called simply Yellow fever virus, named for the jaundice that affects some patients, and belongs to the virus family Flaviviridae. Yellow fever is endemic in areas of Latin America and Africa, while imported cases have appeared throughout the world. Globally, the disease infects about 200,000 people per year, causing fever, chills, nausea, vomiting, muscle pain, and headache, and has no cure. There is no direct treatment for yellow fever. Supportive care may be provided, including efforts to reduce pain and to lower the fever associated with the disease. Medications used for pain relief must be carefully selected, as some nonsteroidal anti-inflammatory drugs (including aspirin) may increase bleeding risk. While many yellow fever patients recover after 3-4 days of symptoms, approximately 15% enter a second phase of the illness after a remission. This second phase includes a return of high fever, as well as jaundice; abdominal pain and vomiting; bleeding from the mouth, nose, eyes, or stomach; and deteriorating kidney function. As many as half of the patients who experience the second phase may die. In all, yellow fever kills 30,000 people globally each year. The yellow fever vaccine provides protection for 30 years or more—possibly for life—and for 95% of those vaccinated, offers protective immunity against the disease within a week. See History of Vaccines

–Lassa Fever:  Though first described in the 1950s, the virus causing Lassa disease was not identified until 1969. The virus is a single-stranded RNA virus belonging to the virus family Arenaviridae. About 80% of people who become infected with Lassa virus have no symptoms. 1 in 5 infections result in severe disease, where the virus affects several organs such as the liver, spleen and kidneys.  Lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals. The animal reservoir, or host, of Lassa virus is a rodent of the genus Mastomys, commonly known as the “multimammate rat.” Mastomys rats infected with Lassa virus do not become ill, but they can shed the virus in their urine and faeces. Because the clinical course of the disease is so variable, detection of the disease in affected patients has been difficult. When presence of the disease is confirmed in a community, however, prompt isolation of affected patients, good infection prevention and control practices, and rigorous contact tracing can stop outbreaks. Lassa fever is known to be endemic in Benin (where it was diagnosed for the first time in November 2014), Ghana (diagnosed for the first time in October 2011), Guinea, Liberia, Mali (diagnosed for the first time in February 2009), Sierra Leone, and Nigeria, but probably exists in other West African countries as well.  See WHO

Mononucleosis (“mono” or “kissing disease”):

–cause: This lymphatic system disease can be casued by a number of bacteria or viruses but the vast majority are casued by the Epstein-Barr virus (EBV), a member of the herpesvirus family. 

–signs and umptoms: are sore throat, high fever, and cervical lymphadenopathy, which develop after a long incubation period (30-50 days). Many patients also have a gray white exudate in the throat, a skin rash and enlarged spleen and liver. A notable sign of mononucleosis is sudden leukocytosis (an increase in number of white blood cells), consisting initially of infected B cells and later T cells. Fatigue for a period of weeks is a hallmark of the disease.  Eventually, the strong, cell mediated immune response is decisive in controlling the infection. 

–transmission and epidemiology: more than 90% of the world’s population is infected with EBV. In general, the virus casues no noticeable symptoms, but the time of life when the virus is first encountered seems to matter. In the case of EBV, infection during the teen eyars results in disease about 25% of the time. Direct oral contact and contamination with saliva are the principal modes of transmission, alhtough transfer through blood transfusions, sexual contact and organ transplants is possible. 

–prevention and treamtent: the usual treamtents is symptomatic relief of fever adn sore throat. 

Affecting the Gastrointestinal Tract

Hepatitis: See Outline under “viruses”. 

Affecting the Genitourinary System

Genital Herpes:

–cause: Herpes is caused by herpes implex viruses (HSVs). The types of HSV that have been identified are HSV-1 and HSV-2. Both HSV-1 and HSV-2 can cause gential herpes if the virus contacts the genital epithelium, although HSV-1 is thought of as a virus that infects the oral mucosa, resulting in cold sores or fever blisters. HSV-2 is thought of as the genital virus. In reality, either virus can infect either region. Herpresviruses have a strong tendency to become latent. During latency, some type of signal causes not of the HSV genome not to be transcribed. This allows the virus to be maintained within cells of the nervous system between epiosides.   See CDC

–Transmission:  Although hperes is not a nationally reportable disease, 50-80% of adults in the US are seropositive for HSV-1 and 20-40% are positive for HSV-2. Worldwide, the WHO estminates that 4 billion people are infected. Becasue the viruses are relatively sensitive to the environment, transmission is primarily through direct exposure to secretions containig the virus. People with active lesions are the most significant source of infection, but sutdies indicate that genital hperes can be transmitted even when no lesion are present. 

–symptoms: After initial infection one may notice no symptoms or the appearance of a single or multiple vesicles on the genitalia, perineum, thigh and buttocks. The vesicles are small and are filled with a clear fluid. They can be intensely painful to touch. The appearance of lesions the first time can be accompanied by malaise, anorexia, fever and bilateral swelling and tenderness in the groin. Occasionally central nervous system symptoms such as meningitis or encephalitis can develop. 

–Prevention: no vaccine is currenlty licended but one is being tested in clinical trails. Condoms provide good protection when they cover the site where the lesion is, but lesions can occur outside of the area covered by a condom. 

–Treatment: Acyclovir and its derivative , famiclovir or valacyclovir, are very effective. Topical formulations can be applied directly to lesions and pills are available as well.

Human Papillomavirus Infection (HPV):

–cause: HPVs are a group of nonenveloped DNA viruses belonging to the Papovaviridae family. There are more than 100 different types of HPV. Some types are specific for teh mucous membranes while others invade the skin. Some of these viruses are the cause of plantar warts, which often occur on the soles of the feet. Other HPVs cause the common warts and flat wards. Others colonize the genital tract such as on the cervix and can lead to cancerous changes. See FDA

–Transmission: nearly all sexually active adults will get HPV at some time in their lives. The mode of transmission is direct contact. Autoinoculation is also possible meaning that the virus can be spread to other parts of the body by touching warts.  See WHO

–Virulence: The major virulence factor for cancer cuasing HPV is their oncogenes, which code for proteins that interfer with normal host cell function, resulting in uncontrolled growth. 

–Prevention: Vaccines prevent infection by up to nine tyeps of HPV.  

–Detection: 

PCR based screening tests can be used to test samples form a pelvic exam ofr the presence of dangerous HPV types. The Pap smeear is still the best screening prcoedure and can detect all precancerous cells if conducted on the recommended schedule.

Most peope who receive abnormal cervical cancer screening results either have HPV ifections or have early cell changes that can be monitored (since they often go away on their own) or reated early (to prevent the development of cervical cancer). A negative HPV test results means that high risk HPV was not found. One should test i 5 years unless there were abnormal resutls in the past. A positive HPV test means that high risk HPV was found. Follow up steps can be taken based on one’s specific test result. ]Pap test results show whetehr cervical cells are normal or abnormal. Normal results indicate no abnormal cervical cells were found. Abnormal pap test results include 1) atyypical squamous cells of undertermined significant (ASC-US) which is the most common abnormal Pap test finding and means that some cells do not look completely normal but it is not clear if the changes are casued by HPV infection, atypical glandular cells (AGC) whgich indicates that some glandular cells were found that do not look normal, low-grade squamous intraepitheial lesions (LSIL) which indicates that there are low grade changes that are usually casued by an HPV infection an datypical squamous cells, cannot exlude high grade squamous intraepithelia lesion (ASC-H) which indicates that some abnormal squamous cells were found that may be a high grade squamous intraepiethelia lesion (HSIL), although it is not certain, high-rade squamous intraepithelialleisions (HSIL0 which indciates that there are moederately or severely abnormal cervical cells that culd become cancerous if not treated, adenocarcinoma in situ (AIS) which indicates an advanced lesion (area of abnormal growth) which was found in the glandular tissue of the cervix and cervical cancer cells (squamous cell carcinoma or adenocarcinoma) which indicates that cancer cells were found (this result is rare for people who ahve been screened at regulr intervals). (National Cancer Institute, “HPV and Pap Test Results: Next steps after an abnormal test”)

–Treatment:

Infection with any HPV is incurable, alhtough they may resolve over a period of months to years. Genital warts can be removed through a variety of methods, but that does not eliminate the virus. 

The most common treatment for high grade cervical cell changes is conization, the removal of a cone shaped pieces of tissue form the ervix and cervical canal. Tehre are two types of conization 1) loop electrosurgical excision proecure (LEEP) which sues a thin wire loop, through which an electrical current is passed to remove abnormal tissue and (2) cold knife conization which uses a scalpel to remove the abnormal tissue which is done at the hospital under general anesthesia. Laser therapy, cryotherapy and total hysterectomy are other options. (National Cancer Institute, “HPV and Pap Test Results: Next steps after an abnormal test”)

Molluscum Contagiosum:

–-cause. MC is caused by an unclassified virus in the fmaily Poxviridae. 

–transmission: MC can be transmitted through fomites such as clothing or towels and through autoinoculation. It can also be transmitted sexually. 

–symptoms: This disease can take the form of skin lesions. The wartlike growths that result from this infeciton can be found on the mucous membranes or the skin of the genital area. Few problems are associated with these growths beyond the warts themselves. 

–treatment: the warts can be removed but the virus is not treatable. 

Affecting the Nervous System

Meningitis: The majority of cases of viral meningitis occur in children, and 90% are casued by enteroviruses. A common cause of viral meningitis is initial infection with HSV-2, concurrent with a genital infection. But many other virsues also gain access to the CNS on occasion. Viral meningitis is generally milder than bacterial or fungal meningitis, and it is usually resolved within 2 weeks. 

Arbovirus Encephalitis: Encephalitis (inflammation of the brain) can present as acute or subacute. One category of viral encephalitis is casued by virsues borne by insects (called arboviruses, which is short for arthropod-borned virsues), including Wist Nile virus, Alternatively other virsues sucha s the JC virus and members fo the herpes family cre causative agents. The signs and tymptoms of encephalitis vary, but may include behaviro changes or confusion becasue of inflammation. Dcreased consciousness and seizures frequently occur. Symtpoms of meningitis are often also present. Few of these agents have specific treatments, but becasue sift initiation of acyclovir theraphy can save the life of a patient suffering from herpesvirus encephalitis, most physicians will begin empiric therapy with acryclovir in all seriously ill neonates adn msot other patients showing evidence of encephalitis. 

–—Eastern Equine Encephalitis Virus: is endemic to an area along eastern cost of North America and Canada. The pattern is sporadic but epidemics can occur in humans and horses. A vaccine exsits for horses and is strongly recommended to eliminate the virus from its reservoir in humans. The case fatality can be 70%. 

One case of eastern equine encephalitis virus disease was reported. The pateint was a woman >60 will illness onset in August. The patient expeirenced neuroinvasive disease and was hospitalized. (Sutter, “West Nile Virus and other nationally notifiable arboviral diseases -United States, 2022” MMWR, 2024, 73(21))

––La Cross Virus: has only been reproted in the eastern half of the U.S. adn in Texas. It is maintained by infection of small mammals, such as sequirrels and chipmunks. Mosquitoes are the vector. Worst form of the disease occurs primarily in children udner 16.

Twent-two cases of La Crosse virus disease were reported form 19 counties in 5 states. Twenty (91%) patients pericenced ilness onset during July-September. The median patient age was 9 years and 55% were male. Nineteen (86%) pateints had neuroinvasive disease. Twenty-one (95%) patients were hospitalized; none died. Ohio reported the highest number o neuroinvasive disease cases. (Sutter, “West Nile Virus and other nationally notifiable arboviral diseases -United States, 2022” MMWR, 2024, 73(21))

—-Jamestown Canyon Virus: is maintained in nature by cycling between mosquitos and der or moose. The virus is found throughout North American.

Among 12 cases of Jamestown Canyon virus disease reported form 12 counties in 5 states, ilness onset occurred most frequently during April-June. The median patient age was 60 and 9 of the 12 patietns were male. All but one patient had neuroinvasive disease and 1 patients were hospitalized; no deaths were reported. Wisconsin reported the highest number of neuroinvasive disease cases (4) and the highest incidence (0.18 per 100k) of neuroinvasive disease occurred in Rhode Island. (Sutter, “West Nile Virus and other nationally notifiable arboviral diseases -United States, 2022” MMWR, 2024, 73(21))

—-Powassan Virus: is maintained in nature by ticks and groundhogs. It is found int he Northeast and the Great Lakes tates. St. Luis Encephalitis Virus: shows no symptoms. The virus is maintained in birds, and transferred by mosquitos to the dead end host, humans. Severe nueroinvasive damage is more common in adults.

forty-seven cases of Powassan virus disease were reported form 39 counties in 9 states. In 2022, Powassan virus disease was reported form Vermont for the first time. Illness onset occurred most fequently during April-Une (45%). Modian patient age was 64 years, and 55% of patients were male. Forty-three (91%) patietns experience neuroinvasive disease, 45 (96%) patients were hospitalized and seven (15% died. States with the highest incidence of neuroinvasive disease included Main (0.29 per 100k), Connectivut (0.17) and Vermont (0.15). All patients who died were >60. (Sutter, “West Nile Virus and other nationally notifiable arboviral diseases -United States, 2022” MMWR, 2024, 73(21))

—-West Nile Virus: emerged in the U.S. in 1999. 70-80% who are infected ahve no symtpoms. Birds are the ampoliyfing hsots. Humans and other large mammals are dead-end hosts.  See Center for Health Production

–JC Virus (JCV) gets its name form the initials for the pateint in whom it was first diagnosed. In patietns with immune dysfunction such as AIDS patietns, it can casue a condition called “progressive multifocal leukoencephalopathy”. Thsi uncommon but generally fatal infection is a result of JC virus attack of accessory brain cells. The infection demyelinizes certain parts of the cerebrum. The virus should be considered when encephalitis symptoms are observed in AIDS pateints. Recently a few deaths from the condition ahve been prevented with high doses of zidovudine. 

 –Herpes Simplex Virus (HSV): Herpes simplex type 1 and 2 viruses can cause encephalitis in newbrons born to HSV positive mothers. Older children and young adults as well as older adults (over 50) are also suspeptible to herpes simplex encephalitis casued most commonly by HSV-1. In these cases, the HSV encephalitis usually represents a reactivation of dormant HSV form the trigeminal ganglion. The varicella-zoster virus (causes chickenpox and perpes zoster (shingles) can also reactive from the dormant state, and it is responsbile for rare cases of encephalitis. (see beow)

–-Oropouche virus can cause encephalitis. Oropouche virus disease in the Americas region, originating from endemic areas in the Amazon basin and new areas in South America and the Caribbean. Between January 1 and August 1, 2024, more than 8,000 cases of Oropouche virus disease were reported, including two deaths and five cases of vertical transmission associated with fetal death or congenital abnormalities. Countries reporting cases include Brazil, Bolivia, Peru, Colombia, and Cuba. It belongs to the Simbu serogroup of the genus Orthobunyavirus in the Peribunyaviridae family. The virus was first detected in 1955 in Trinidad and Tobago. Sylvatic (enzootic) transmission of Oropouche virus occurs in forested areas between mosquitoes and non-human vertebrate hosts (e.g., sloths, non-human primates, domestic and wild birds, and rodents). Humans can become infected while visiting forested areas and are likely responsible for introducing the virus into urban environments. Humans contribute to the transmission cycle in urban environments since infected humans develop sufficient viremia to serve as amplifying hosts. Biting midges (Culicoides paraensis) and possibly certain mosquitoes (Culex quinquefasciatus) are responsible for transmitting the virus from an infected person to an uninfected person in urban areas. Approximately 60% of people infected with Oropouche virus become symptomatic. he incubation period is typically 3–10 days. Initial clinical presentation is similar to diseases like Dengue such as acute onset of fever, chills, headache, myalgia, and arthralgia. See CDC

Varicella is an illness characterized by a generalized, pruritic rash adn transmitted thorugh airbonre, droplet, and contact transmission. Alhtough varicella causes mild to moderate systmptomes, serious complications, including pneumonia and death can occur. In October 2022, the NYC Department of Health and Mental Hygiene idneitfied a varicella outbreak primarily involving persons who recently migrated from or thorugh Central and South America and lived in an NYC shelter or residentail facility.

–-Varicella-zoster virus (VZV) is responsible for both varicella (chickenpox) and herpes zoster (shingles). During varicella, the virus establishes latency within the sensory ganglia and can reactivate to cause herpes zoster, but the immune responses that occur in ganglia during herpes zoster have not previously been defined. See Stainne

Varicella-zoster virus (VZV) is a human alphaherpesvirus that infects >90% of people worldwide. Primary VZV infection, typically acquired during early childhood, leads to varicella (chickenpox) and establishment of a lifelong latent infection in neurons of trigeminal ganglia (TG) and dorsal root ganglia (DRG). Later in life, VZV reactivates in approximately one third of infected individuals to cause herpes zoster ([HZ] shingles). See Laing

Varicella-zoster virus (VZV) is a medically important human alphaher-pesvirus that causes varicella and zoster. VZV initiates primary infection by inoculation of the respiratory mucosa. In the course of primary infection, VZV establishes a life-long persistence in sensory ganglia; VZV reactivation from latency may result in zoster in healthy and immunocompromised patients. The VZV genome has at least 70 known or predicted open reading frames (ORFs), but understanding how these gene products function in virulence is difficult because VZV is a highly human-specific pathogen. See Arvin

Poliomyelitis (polio): is an acute enterovival infection of the spinal cord that casue casue neuromuslular paralysis. Becasue it often affects small children, in the past it was called “infantile paralysis”. Most infections are contained as short term, mild viremia. In paralytic disease, invasion of motor neurons casues various degress of flaccid (floppy) paralysis over a period of a few hours to several days. The poliovirus is int he fmaily Picornaviridae, genus Enterovirus, named for its small (pico) size and its RNA genome. It is a nonenveloped and nonsegmented. Human are the only known reservoir. The virsu is passed within the population through food, water, hands, obtects contaminated with feces, adn mechincal vectors. Although the 20th centruy saw a very large rise in paralytic polio cases, effective vaccines were developed. The infection was eliminated form teh Western Hemisphere in the late 20th centrue. Since the virus cannot exist outside of a human, it is possible to totally eradicate the disease if we vaccinate all susceptible hosts. 

Rabies: is a slow, progressive zoonatic disease characterized by a fatal encephalitis. The average incubation period of rabies is 1-2 months or more, dpending on the wound site, its severity and inoculation dose. The incubation period is shorter in facila, scalp or neck wounds becasue of clsoer proximity to the brain. The prodromal pahse starts with fever, nausea, vomiting, headache, fatigue and other nonspecific symptoms. Infection with rabies virus typically begins when an infected animal’s saliva enters a puncture site. The virus occasionally is inhaled or inoculated through the membrnes of the ye. The virus remains up to a week at the trauma site, where it multiples. The virus then gradually enters never endings and advances toward the ganglia, spinal cord and brain. Globally, over 905 of human rabies cases are still azquired from dogs. A bite from a wild or stray animal demands assessment of the animal, meticulous care of the wound, and a specific treatment regimen. A wild mammal, especially a skunk, raccon, fox or coyote that bites without provocation is presumed to be rabid, and therapy for rabies is immediately started. A combination of passive and active postexposure immunization is successful. Initially the wound is infused with human rabies immune globulin to impede the spread of the virus, and globulin is also injected intramuscularly to provide immediate systemic protection. A full course of vaccination is started simultaneously. The routine postexposure vaccination enails intramuscular or intradermal injection on days 0, 3, 7 and 14, sometimes with two additional boosters. 

Tick-borne Encephalitis (TBE) virus: is a tickborne flavivrus taht is focally endemic in a geographic region extending form westerna nd northern Europe thorugh to northern and eastern Asia. TBE virus is a single=stranded RNA virus in the genus Flavivirus family Faviviridae. TBE virus is closely related to Powassan virus, a tickborne flavirus transmitted in parts of the U.S. The three main antigenic subtypes of TBE virus (e.e., European, Siberian, and Far Eastern) differ in the severity of disease they cause and geographic distribution. The most recognized clinical manifestation of TBE virus infection is acute neurologic disease, which usually results in hospitalization, often permanent neurologic or cognitive sequelae, and sometimes death. TBE is rare among travelers and laboratory workers. In August 2021, the FDA approved an inactivated TBE vaccine for use in persons aged more than 1. The TBE virus is primarily transmitted to humans by the bites of infected txodes sp. ticks. The preferred habitats for the vector ticks are woodland enviornments. (MMWR, “Tick-borne encephalitis vaccine: recommendations of the advisory committee on immunizaiton practices, United States, 2023”. 

Zika Virus: Starting in 2015 adn continuing into 2016, an epidemic of babies born with abnromally small heads, a condition called microcephaly, became obvious in Brazil. The cause was quickly determinedto be the Zika virus. Zika virus is an RNA virus is int he Flaviviridae family. It is closely related to viruses casuing dengue fever, West Nile fever and yellow fever.

 During 2016, the virus spread rapidly through the Americas adn cotninues to do so. Its mosquito host, the genus Aedes, is spread throughout the world. The best way to prevent Zika is to prevent mosquito bites by using insect repellent, wearing long-sleeved shirts and pants and staying in places with air conditioning or window and door screens. Remvoing standing water is also very improtant.

When adults are infected with Zika, they can experience a range of symptoms, from none at all, to a skin rash, conjunctivitis, and muscle and joint pian. The virus also appears to trigger Guillain-Barre syndrome (GBS) in some adutls. GBS is a neurological conditions that can occur after infections with certain bacteria and viues, adn soemtimes after exposure to vaccines. 

Affecting the Respiratory System 

See “Respiratory Viruses” under “viruses”

Bronchiolitis is a common lung infection in young children and infants. It causes inflammation and congestion in the small airways (bronchioles) of the lung. Bronchiolitis is almost always caused by a virus. Typically, the peak time for bronchiolitis is during the winter months. Most cases of bronchiolitis are caused by the respiratory syncytial virus (RSV). RSV is a common virus that infects just about every child by 2 years of age. Outbreaks of RSVinfection occur every winter, and individuals can be reinfected, as previous infection does not appear to cause lasting immunity. Bronchiolitis also can be caused by other viruses, including those that cause the flu or the common cold. See Mayo Clinic.