Clinical data from A129 mice challenged with different strains of ZIKV^AS.

<p>5–8 week old A129 mice were subcutaneously challenged with 10⁶ pfu ZIKV^AS virus. (A) Kaplin-Meier survival plot. (B) Differences in weight compared to date of challenge. (C) Temperature change compared to date of challenge. Graphs B and C show the mean values with error bars denoting standard error. Group sizes were n = 5.</p

Histological and RNA <i>in situ</i> hybridisation findings in the spleen, testes and heart of ZIKV-challenge A129 mice.

<p>(A) Spleen. Poorly defined areas comprising large mononuclear cells within the white pulp (Animal 86783, 10⁶ pfu ZIKV^AF, day 5). Inset, normal spleen with well defined, small germinal centres within the white pulp (Animal 86739, unchallenged). (B) Spleen. Prominent, extra-medullary haematopoiesis in the red pulp. Rectangle, numerous PMNs in the red pulp sinuses (Animal 86724, 10⁶ pfu ZIKV^AF, day 7). (C) Testis. Expansion of the interstitial tissue by proteinaceous fluid, macrophages and PMNs. Inset, higher power image of area within white square (Animal 86772, 10 pfu ZIKV^AF, day 5). (D) Testis. Mild infiltration of PMNs into the interstitial space with positive viral staining (Animal 86779, 10⁶ ZIKV^AF, day 3). (E) Testis. Positive staining of virally infected cells focally within the walls of the seminiferous tubules (white arrows) as well as within the interstitium (Animal 86784, 10 pfu ZIKV^AF, day 7). (F) Testis. Epididymis with positive staining of cells in lumen and epithelium of the efferent ductules as well as the interstitium (Animal 86784, 10 pfu ZIKV^AF, day 7). (G) Testis. Positive staining of cells in the necrotic seminiferous tubules (Animal 86744, 10⁶ pfu ZIKV^AS, day 14). (H) Testis. Intra-tubular and interstitial cell staining (Animal 86757, 10⁶ pfu ZIKV^AS, day 7). (I) Heart. Infiltration of myocardium by macrophages and PMNs (Animal 86779, 10⁶ ZIKV^AF, day 3). (J) Heart. Infiltration of an atrio-ventricular valve by macrophages and PMNs (Animal 86780, 10⁶ pfu ZIKV^AF, day 3). A-C and I-J show sections stained with haematoxylin and eosin (H&E) and D-H show RNA <i>in situ</i> hybridisation images.</p

Histological and RNA <i>in situ</i> hybridisation findings in the brain of ZIKV-challenge A129 mice.

<p>(A) Scattered nuclear fragmentation in the hippocampus (Animal 86756, 10⁶ pfu ZIKV^AS, day 7). (B) Perivascular cuffing by mononuclear cells (Animal 86762, 10⁶ pfu ZIKV^AS, day 7). (C) Scattered polymorphonuclear cells (PMNs) in the neuropil, including higher magnification of PMNs (Animal 86722, 10⁶ pfu ZIKV^AF, day 7). (D) Diffuse neuronal degeneration in Ammon’s horn of hippocampus (Animal 86724, 10⁶ ZIKV^AF, day 6). (E) Infiltration of inflammatory cells, mainly mononuclear, in the meninges (Animal 86765, 10 pfu ZIKV^AF, day 7). (F) Occasional scattered cells staining positive for viral RNA in the hippocampus (Animal 86780, 10⁶ pfu ZIKV^AF, day 3). (G) Patchy to diffuse positive staining for viral RNA in the hippocampus (Animal 86783, 10⁶ pfu ZIKV^AF, day 5). (H) Strong positive staining for viral RNA (Animal 86740, 10 pfu ZIKV^AF, day 7). (I) Focus of positively staining cells for viral RNA in sub-ependymal area of the fourth ventricle (Animal 86773, 10⁶ ZIKV^AS, day 5). A-E show sections stained with haematoxylin and eosin (H&E) and F-I show RNA <i>in situ</i> hybridisation images.</p

Genetic sequence similarities between ZIKV strains using the study.

<p>Genetic sequence similarities between ZIKV strains using the study.</p

Histological findings in spleen, liver, testis and heart of A129 mice infected with ZIKV.

<p>Histological findings in spleen, liver, testis and heart of A129 mice infected with ZIKV.</p

Clinical data and viral burden from A129 mice challenged with ZIKV^AF and ZIKV^AS.

<p>6–8 week old A129 mice were subcutaneously challenged with a high (10⁶ pfu) or low (10 pfu) dose of ZIKV^AF or ZIKV^AS. At days 1, 3, 5 and 7 post-challenge, a cohort of mice from each group were culled for assessment of local response. (A) Kaplin-Meier survival plot. (B) Differences in weight compared to day of challenge. (C) Differences in temperatures compared to day of challenge. (D) Clinical score, with numerical values given as follows: 0, normal; 2, ruffled fur; 3, lethargy, pinched, hunched, wasp waisted; 5, laboured breathing, rapid breathing, inactive, neurological; and 10, immobile. (E) Viral burden in local tissues (spleen, liver, brain, kidney, lung, testes, heart and blood) at days 1, 3, 5, 7 and 14 post-challenge. (F) Viral burden in secretions (saliva and rectal swabs) of animals at days 1, 3, 5, 7 and 14 post-challenge. Graphs A-D: group sizes were n = 6.Graphs B—D show the mean values with error bars denoting standard error. Graphs E-F: groups sizes of n = 3, with bar denoting mean values and error bars denoting standard error. Abbreviations: <, below the limit of detection; x, no results as animals had previously met humane endpoints; and *, statistical significance (P = 0.0809, Mann-Whitney test).</p

Viral RNA staining in tissues from A129 mice challenged with ZIKV.

<p>Viral RNA staining in tissues from A129 mice challenged with ZIKV.</p

Histological findings in brains of A129 mice infected with ZIKV.

<p>Histological findings in brains of A129 mice infected with ZIKV.</p

Clinical data from A129 mice challenged with different doses of ZIKV^AF.

<p>6–8 week old A129 mice were subcutaneously challenged with 10⁶, 10⁵, 10⁴, 10³, 10² or 10 pfu ZIKV^AF virus. (A) Kaplin-Meier survival plot. (B) Differences in weight compared to date of challenge. (C) Clinical score, with numerical values given as follows: 0, normal; 2, ruffled fur; 3, lethargy, pinched, hunched, wasp waisted; 5, laboured breathing, rapid breathing, inactive, neurological; and 10, immobile. Graphs B and C show the mean values with error bars denoting standard error. Group sizes were n = 5.</p

Non-Replicating <i>Mycobacterium tuberculosis</i> Elicits a Reduced Infectivity Profile with Corresponding Modifications to the Cell Wall and Extracellular Matrix

<div><p>A key feature of <i>Mycobacterium tuberculosis</i> is its ability to become dormant in the host. Little is known of the mechanisms by which these bacilli are able to persist in this state. Therefore, the focus of this study was to emulate environmental conditions encountered by <i>M. tuberculosis</i> in the granuloma, and determine the effect of such conditions on the physiology and infectivity of the organism. Non-replicating persistent (NRP) <i>M. tuberculosis</i> was established by the gradual depletion of nutrients in an oxygen-replete and controlled environment. In contrast to rapidly dividing bacilli, NRP bacteria exhibited a distinct phenotype by accumulating an extracellular matrix rich in free mycolate and lipoglycans, with increased arabinosylation. Microarray studies demonstrated a substantial down-regulation of genes involved in energy metabolism in NRP bacteria. Despite this reduction in metabolic activity, cells were still able to infect guinea pigs, but with a delay in the development of disease when compared to exponential phase bacilli. Using these approaches to investigate the interplay between the changing environment of the host and altered physiology of NRP bacteria, this study sheds new light on the conditions that are pertinent to <i>M. tuberculosis</i> dormancy and how this organism could be establishing latent disease.</p></div