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Deposition of Burkholderia pseudomallei within either the lungs or nasal passages of the Balb/c murine model resulted in different infection kinetics. The infection resulting from the inhalation of B. pseudomallei within a 12 μm particle aerosol was prolonged compared to a 1 μm particle aerosol with a mean time-to-death (MTD) of 174.7 ± 14.9 h and 73.8 ± 11 .3 h, respectively. Inhalation of B. pseudomallei within 1 μm or 12 μm particle aerosols resulted in a median lethal dose (MLD) of 4 and 12 cfu, respectively. The 12 μm particle inhalational infection was characterized by a marked involvement of the nasal mucosa and extension of bacterial colonization and inflammatory lesions from the olfactory epithelium through the olfactory nerves (or tracts) to the olfactory bulb (100%), culminating in abscessation of the brain (33%). Initial involvement of the upper respiratory tract lymphoid tissues (nasal-associated lymphoid tissue (NALT) and cervical lymph nodes) was observed in both the 1 and 12 μm particle inhalational infections (80-85%). Necrotising alveolitis and bronchiolitis were evident in both inhalational infections, however, lung pathology was greater after inhalation of the 1 μm particle aerosol with pronounced involvement of the mediastinal lymph node (50%). Terminal disease was characterized by bacteraemia in both inhalational infections with dissemination to the spleen, liver, kidneys, and thymus. Treatment with co-trimoxazole was more effective than treatment with doxycycline irrespective of the size of the particles inhaled. Doxycycline was more effective against the 12 μm particle inhalational infection as evidenced by increased time to death. However, both treatment regimes exhibited significant relapse when therapy was discontinued with massive enlargement and abscessation of the lungs, spleen, and cervical lymph nodes observed. [ABSTRACT FROM AUTHOR]

Aims: Filoviruses are associated with high morbidity and lethality rates in humans, are capable of human-to-human transmission, via infected material such as blood, and are believed to have low infectious doses for humans. Filoviruses are able to infect via the respiratory route and are lethal at very low doses in experimental animal models, but there is minimal information on how well the filoviruses survive within aerosol particles. There is also little known about how well filoviruses survive in liquids or on solid surfaces which is important in management of patients or samples that have been exposed to filoviruses. Methods and Results: Filoviruses were tested for their ability to survive in different liquids and on different solid substrates at different temperatures. The decay rates of filoviruses in a dynamic aerosol were also determined. Conclusions: Our study has shown that Lake Victoria marburgvirus (MARV) and Zaire ebolavirus (ZEBOV) can survive for long periods in different liquid media and can also be recovered from plastic and glass surfaces at low temperatures for over 3 weeks. The decay rates of ZEBOV and Reston ebolavirus (REBOV) plus MARV within a dynamic aerosol were calculated. ZEBOV and MARV had similar decay rates, whilst REBOV showed significantly better survival within an aerosol. Significance and Impact of the Study: Data on the survival of two ebolaviruses are presented for the first time. Extended data on the survival of MARV are presented. Data from this study extend the knowledge on the survival of filoviruses under different conditions and provide a basis with which to inform risk assessments and manage exposure to filoviruses. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the ability to survive in an aerosol leads to better understanding of the hazard posed by pathogenic organisms and can inform decisions related to the control and management of disease outbreaks. This basic survival information is sometimes lacking for high priority select agents such as the filoviruses which cause severe disease with high case fatality rates and can be acquired through the aerosol route. Microthreads in the form of spiders’ webs were used to capture aerosolised filoviruses, and the decay rates of Zaire ebolavirus and Marburgvirus were determined. Results were compared to data obtained using a Goldberg drum to measure survival as a dynamic aerosol. The two methods of obtaining aerostability information are compared. [Copyright &y& Elsevier]