CMV (cytomegalovirus) is an exogenous agent of broad clinical range to produce severe organ failure in immunosuppressed people. It belongs to the family of herpes viruses which is known as HHV-5 (human herpes virus-5) or Herpesviridae mostly linked to salivary glands. These infections are serious and terminal in immunocompromised patients which results in morbidity and mortality. The percentage of CMV infected persons revealed adult people in industrialized country 60% to 70% whereas in the emerging country 100% people were affected by CMV virus. It boasts largest number of genes specifically devoted to evasion of the host innate and adaptive immune systems. CMV is one of the most common infections that result in deafness, intellectual deficit, and learning impairments.  

Almost 59% above 6 years of age have been unveiled to CMV which displayed an elevated seroprevalence along with an increase in age. This infection generally happens like a primary infection, reactivation or reinfection. Virus can be transmitted in many ways through breast feeding, organ transplantation, transfusions, perinatally, and sexual transmission where shedding of virus in close contacts. In patients related to increased mortality, morbidity, and immunocompromised reactivation can be noticed. 

CMV infection: identification of the virus in tissue and urine or blood. 

Recurrent infection: Reactivation or reinfection in seropositive people. 

Primary infection: presence of infection in seronegative cases who might be asymptomatic. 

CMV disease: infection due to CMV is linked to end-organ involvement and non-specific symptoms and signs. 

After transmission of CMV and resolution of primary infection, the virus goes into latency and resides in the myeloid cells. Essential reactivation and replication are mostly controlled by immunity due to cytotoxic T-cells. However, at time of reactivation, the virions enter the blood and other body fluids, therefore, causing the appearance of symptoms mostly in the immunocompromised population. 

CMV belongs to the category of Herpesviruses and is a DNA virus that is double-stranded. Like other herpesviruses, the disease is most likely associated with CMV, after the appearance of the first signs, subsides and the virus remains in the host organism. This occurs at the period where there is immune suppression of the herpesvirus in the body besides immune breakdown. 

The outcome for many patients suffering from CMV is generally favorable, provided they are not immunosuppressed. With appropriate treatment, recovery is typically complete, although fatigue can linger for several months. 

Adult CMV infection in the immunocompetent 

CMV infection exist in immunocompetent hosts in various sites including spleen, CNS, liver, and hematologic system. It can cause mononucleosis syndrome similar to primary Epstein-Barr virus infection, acute HIV seroconversion, and primary toxoplasmosis.  

In a large series of 494 cases of infectious mononucleosis 79% were due to EBV infection with nearly half being CMV positive. Both EBV and CMV may cause atypical lymphocytes in blood. In immunocompetent hosts fever or clinical mononucleosis of unknown cause should be suspected.  

In rare cases, community-acquired pneumonia may be due to CMV infection. In critically ill patients CMV reactivates and leading to longer hospital stays which extends mechanical ventilation, increased mortality, and morbidity. 

Adult CMV infection in the immunocompromised host 

CMV infection is risk in patients with allogenic HSCT with poor outcomes and increased prevalence in advanced age. Positive recipients of IgG from CMV seronegative supporters have worst outcomes. CMV is a significant pathogen in organ transplantation with severe primary infections occurring in recipient-negative and donor-positive transplants. Immunocompromised patients may develop life-threatening CMV pneumonia by presenting with fever and difficulty breathing. 

The majority of patients suffering with infection due to CMV show some clinical observations of which few of them are provided: 

1. Pharyngitis scan be noticed 
2. Obvious symptoms may begin in nine to sixty days post primary infection. 
3. Fever due to unidentified cause 
4. Fine crackles may be seen in lung manifestations 
5. Enlarged lymph nodes and spleen 

Transplant patients experience relapse 

• Medical care: Treatment approaches for CMV vary according to the status of the patient and co-morbidities. Prophylaxis is given to prevent recurrent, primary or reactivation of infection, while preemptive treatment is advised to CMV-infected patients who are asymptomatic and detected with screening tests. Letermovir, a newest inhibitor of viral terminase, has been employed in prevention of CMV in allo-HSCT seropositive patients but it has not received approval for recipients of solid organ transplant. 
• Activity: Many patients with active CMV infection ask how long they will be able to resume activities. Common symptoms after the acute phase of the CMV infection resolves include fatigue. This can last for up to 18 months after the primary infection, although it usually is much shorter. Some patients only rest a few days and then return to their normal routine, however recovery from fatigue averaged one to two months.  

Infectious Disease

To improve patient outcomes and reduce complications for healthcare providers should implement several strategies for treating cytomegalovirus. These include enhanced infection control measures, isolation protocols, monitoring and screening, optimizing immune function, antiviral therapy, supportive care and education and training. Enhanced infection control measures that involves strict hygiene practices, sterilization of medical equipment, and isolation protocols. Isolation protocols involve placing immunocompromised patients in isolation and using negative pressure rooms to contain airborne particles. Optimizing immune function involves adjusting immunosuppressive therapies and considering immune-boosting treatments. Supportive care includes managing symptoms, complications, education, and training on CMV management and treatment protocols. 

Infectious Disease

• Ganciclovir: This is a nucleoside analog of guanine synthetic derivative that acts against CMV by inhibiting viral replication. 
• Foscarnet: It suppresses the replication of HSV-1, HSV-2, and CMV viruses at phosphate binding site in DNA polymerases that are specific to viruses. 
• Cidofovir: This is used in treating CMV retinitis in people suffering with AIDS. Introduction of cidofovir into developing DNA chain of virus leads to reduced speed of viral DNA synthesis. 
• Letermovir: This belongs to the novel category of non-nucleoside CMV inhibitors. It is active in the final stages of replication of viruses. It is employed as a prophylactic therapy in CMV infection. 

Infectious Disease

CMV IG (cytomegalovirus immune globulin): It is indicated to provide passive immunity via neutralization and help in removal of circulating particle of CMV. It is particularly useful in treating CMV pneumonia. 

Infectious Disease

Leflunomide: It is indicated in prevention of chronic and acute rejection. It is known to inhibit pyrimidine synthesis which leads to antiproliferative and immunomodulatory activity. 

Infectious Disease

The management of CMV infection in immunocompromised individuals involves prevention, early detection, initial management, maintenance therapy, long-term follow-up, persistent-symptom management, patient education, and support services.