Tissue and cellular tropism, pathology and pathogenesis of Ebola and Marburg viruses.

Ebola viruses and Marburg viruses include some of the most virulent and fatal pathogens known to humans. These viruses cause severe haemorrhagic fevers, with case fatality rates in the range 25-90%. The diagnosis of filovirus using formalin-fixed tissues from fatal cases poses a significant challenge.

Alteration of the phenotypic and pathogenic patterns of Burkholderia pseudomallei that persist in a soil environment.

Melioidosis is caused by the soil-borne pathogen Burkholderia pseudomallei. To investigate whether the distinct phenotypic and virulent characteristics result from environmental adaptations in the soil or from the host body, two pairs of isogenic strains were generated by passages in soil or mice. After cultivation in soil, the levels of 3-hydroxytetradecanoic acid, biofilm formation, flagellar expression, and ultrastructure were altered in the bacteria.

Exserohilum infections associated with contaminated steroid injections: a clinicopathologic review of 40 cases.

September 2012 marked the beginning of the largest reported outbreak of infections associated with epidural and intra-articular injections. Contamination of methylprednisolone acetate with the black mold, Exserohilum rostratum, was the primary cause of the outbreak, with >13,000 persons exposed to the potentially contaminated drug, 741 confirmed drug-related infections, and 55 deaths. Fatal meningitis and localized epidural, paraspinal, and peripheral joint infections occurred.

Diagnosis of influenza from respiratory autopsy tissues: detection of virus by real-time reverse transcription-PCR in 222 cases.

The recent influenza pandemic, caused by a novel H1N1 influenza A virus, as well as the seasonal influenza outbreaks caused by varieties of influenza A and B viruses, are responsible for hundreds of thousands of deaths worldwide. Few studies have evaluated the utility of real-time reverse transcription-PCR to detect influenza virus RNA from formalin-fixed, paraffin-embedded tissues obtained at autopsy. In this work, respiratory autopsy tissues from 442 suspect influenza cases were tested by real-time reverse transcription-PCR for seasonal influenza A and B and 2009 pandemic influenza A (H1N1) viruses and the results were compared to those obtained by immunohistochemistry.

Isolation of genetically diverse Marburg viruses from Egyptian fruit bats.

In July and September 2007, miners working in Kitaka Cave, Uganda, were diagnosed with Marburg hemorrhagic fever. The likely source of infection in the cave was Egyptian fruit bats (Rousettus aegyptiacus) based on detection of Marburg virus RNA in 31/611 (5.1%) bats, virus-specific antibody in bat sera, and isolation of genetically diverse virus from bat tissues.

Pathology and pathogenesis of fatal Bordetella pertussis infection in infants.

Background: Each year, Bordetella pertussis infection causes an estimated 294,000 deaths worldwide, primarily among young, nonvaccinated children. Approximately 90% of all deaths due to pertussis in the Unites States occur in young infants. These children often develop intractable pulmonary hypertension; however, the pathophysiologic mechanism responsible for this complication has not been well characterized, and there have been no detailed descriptions of the pathology of this disease since the 1940s.

Progressive ORF virus infection in a patient with lymphoma: successful treatment using imiquimod.

Orf virus is a parapoxvirus that infects small ruminants worldwide. We present the case report of a 73-year-old woman with non-Hodgkins lymphoma who developed progressive orf virus lesions that were unresponsive to surgical debridement and to cidofovir therapy. The patient's orf virus infection was successfully treated with topical imiquimod despite progression of her malignancy.

Fatal malaria infection in travelers: novel immunohistochemical assays for the detection of Plasmodium falciparum in tissues and implications for pathogenesis.

Plasmodium falciparum is a significant cause of morbidity and mortality in travelers to areas where the parasite is endemic. Non-specific clinical manifestations may result in failure to recognize malaria until autopsy, when it is often too late to obtain whole blood for microscopic evaluation. The use of immunohistochemical (IHC) assays in the detection of three P.

Diagnosis of invasive group a streptococcal infections by using immunohistochemical and molecular assays.

Invasive group A streptococcus (GAS) infections cause 1,100 to 1,300 deaths annually in the United States. Diagnosis is made when Streptococcus pyogenes is isolated from pus or body fluids; however, cultures are not always obtained, and antibiotic treatment can preclude bacterial growth. An immunohistochemical assay for GAS was applied to formalin-fixed tissue samples from 122 patients with suspect GAS infection.

Fatal hemorrhagic fever caused by West Nile virus in the United States.

Background: Most West Nile virus (WNV) infections in humans are asymptomatic; severe disease occurs in relatively few patients and typically manifests as encephalitis, meningitis, or acute flaccid paralysis. A few cases of life-threatening disease with diffuse hemorrhagic manifestations have been reported in Africa; however, this clinical presentation has not been documented for any of the >16,700 cases of WNV disease reported in the United States during 1999-2004. We describe a case of fulminant WNV infection in a 59-year-old Florida man who died following a brief illness that resembled hemorrhagic disease caused by Rickettsia reckettsii, dengue virus or yellow fever virus.

Avian influenza (H5N1) viruses isolated from humans in Asia in 2004 exhibit increased virulence in mammals.

The spread of highly pathogenic avian influenza H5N1 viruses across Asia in 2003 and 2004 devastated domestic poultry populations and resulted in the largest and most lethal H5N1 virus outbreak in humans to date. To better understand the potential of H5N1 viruses isolated during this epizootic event to cause disease in mammals, we used the mouse and ferret models to evaluate the relative virulence of selected 2003 and 2004 H5N1 viruses representing multiple genetic and geographical groups and compared them to earlier H5N1 strains isolated from humans. Four of five human isolates tested were highly lethal for both mice and ferrets and exhibited a substantially greater level of virulence in ferrets than other H5N1 viruses isolated from humans since 1997.

Pathogenesis and diagnosis of human meningococcal disease using immunohistochemical and PCR assays.

Neisseria meningitidis remains the leading cause of fatal sepsis. Cultures may not be available in fulminant fatal cases. An immunohistochemical assay for N meningitidis was applied to formalin-fixed samples from 14 patients with meningococcal disease.

Immunohistochemical detection of Yersinia pestis in formalin-fixed, paraffin-embedded tissue.

Yersinia pestis infection usually is limited to lymph nodes (bubo); rarely, if bacteria are aerosolized, pneumonic plague occurs. We developed an immunohistochemical assay using a monoclonal anti-fraction 1 Y pestis antibody for formalin-fixed tissues. We studied 6 cases using this technique.