Trends in the Epidemiology of Pneumocystis Pneumonia in Immunocompromised Patients without HIV Infection.

The increasing morbidity and mortality of life-threatening Pneumocystis pneumonia (PCP) in immunocompromised people poses a global concern, prompting the World Health Organization to list it as one of the 19 priority invasive fungal diseases, calling for increased research and public health action. In response to this initiative, we provide this review on the epidemiology of PCP in non-HIV patients with various immunodeficient conditions, including the use of immunosuppressive agents, cancer therapies, solid organ and stem cell transplantation, autoimmune and inflammatory diseases, inherited or primary immunodeficiencies, and COVID-19. Special attention is given to the molecular epidemiology of PCP outbreaks in solid organ transplant recipients; the risk of PCP associated with the increasing use of immunodepleting monoclonal antibodies and a wide range of genetic defects causing primary immunodeficiency; the trend of concurrent infection of PCP in COVID-19; the prevalence of colonization; and the rising evidence supporting de novo infection rather than reactivation of latent infection in the pathogenesis of PCP. Additionally, we provide a concise discussion of the varying effects of different immunodeficient conditions on distinct components of the immune system. The objective of this review is to increase awareness and knowledge of PCP in non-HIV patients, thereby improving the early identification and treatment of patients susceptible to PCP.

Coccidioidal meningitis in non-AIDS patients. A case series at a Mexican neurological referral center.

BACKGROUND: Coccidioidal meningitis is a life-threatening condition and a diagnostic challenge in cases of chronic meningitis. It is associated to severe complications, like basal arachnoiditis, hydrocephalus, and secondary vasculitis. OBJECTIVE: To present a 20-year retrospective clinical series of coccidioidal meningitis cases at a Mexican neurological referral center. RESULTS: The clinical records of 11 patients, predominantly males, were retrieved. Weight loss and night sweats were observed in 64 % of cases. Neurological signs included intracranial hypertension in 91 % of cases, altered alertness and meningeal syndrome in 72 %, and neuropsychiatric symptoms in 64 %. Mean CSF glucose levels were 30 ± 25 mg/dL, and pleocytosis ranged from 0 to 2218 cells/mm3. The diagnosis was confirmed by coccidioidal antigen latex agglutination in 91 % of cases. Radiological findings were hepatomegaly in 55 % of cases and pneumonia in 45 %. Neuroimaging findings included leptomeningitis in 73 % of cases, pachymeningitis in 45 %, and vascular involvement in 91 %. Less common findings included spinal cord lesion and mycotic aneurism, found in 18 % of cases. A molecular coccidioidal DNA test confirmed the predominance of Coccidioides immitis, detected in 64 % of cases. With respect to the clinical outcome, 46 % of patients died. The survivors suffered from sequels like chronic headache, cognitive alterations, and depression. CONCLUSIONS: Coccidioidal meningitis is an entity with high mortality rates. More than one half of patients suffered disseminated disease. Although meningeal signs are not frequent in chronic meningitis, more than two-thirds of our patients showed mild nuchal rigidity. In addition, cerebral and cerebellar volume loss, associated with cognitive impairment and depression, was often observed in surviving patients during the clinical-radiological follow-up.

A multi-stage compartmental model for HIV-infected individuals: II--application to insurance functions and health-care costs.

Stochastic population processes have received a lot of attention over the years. One approach focuses on compartmental modeling. Billard and Dayananda (2012) developed one such multi-stage model for epidemic processes in which the possibility that individuals can die at any stage from non-disease related causes was also included. This extra feature is of particular interest to the insurance and health-care industries among others especially when the epidemic is HIV/AIDS. Rather than working with numbers of individuals in each stage, they obtained distributional results dealing with the waiting time any one individual spent in each stage given the initial stage. In this work, the impact of the HIV/AIDS epidemic on several functions relevant to these industries (such as adjustments to premiums) is investigated. Theoretical results are derived, followed by a numerical study.

A multi-stage compartmental model for HIV-infected individuals: I--waiting time approach.

Traditionally, epidemic processes have focused on establishing systems of differential-difference equations governing the number of individuals at each stage of the epidemic. Except for simple situations such as when transition rates are linear, these equations are notoriously intractable mathematically. In this work, the process is described as a compartmental model. The model also allows for individuals to go directly from any prior compartment directly to a final stage corresponding to death. This allows for the possibility that individuals can die earlier due to some non-disease related cause. Then, the model is based on waiting times in each compartment. Survival probabilities of moving from a given compartment to another compartment are established. While our approach can be used for general epidemic processes, our framework is for the HIV/AIDS process. It is then possible to establish the impact of the HIV/AIDS epidemic process on, e.g., insurance premiums and payouts and health-care costs. The effect of changing model parameter values on these entities is investigated.