Surveillance for malaria outbreak on malaria-eliminating islands in Tafea Province, Vanuatu after Tropical Cyclone Pam in 2015.

The risk of malaria outbreak surfaced in Vanuatu after Tropical Cyclone (TC) Pam in March 2015. In June and July 2015 we conducted malariometric surveys on the islands of Tanna, Aneityum, and Erromango in Tafea Province, where malaria elimination had been targeted, to determine if malaria incidence had increased after TC Pam. No Plasmodium infection was detected by microscopy and PCR in 3009 survey participants. Only 6·3% (190/3007) of participants had fever. Spleen rates in children aged ⩽12 years from Aneityum and Tanna were low, at 3·6% (14/387) and 5·3% (27/510), respectively. Overall bed net use was high at 72·8% (2175/2986); however, a significantly higher (P < 0·001) proportion of participants from Aneityum (85·9%, 796/927) reported net use than those from Tanna (67·1%, 751/1119) and Erromango (66·8%, 628/940). A recent decrease in malaria incidence in Tafea Province through comprehensive intervention measures had reduced the indigenous parasite reservoir and limited the latter's potential to spur an outbreak after TC Pam. The path towards malaria elimination in Tafea Province was not adversely affected by TC Pam.

A survey of rodent-borne pathogens carried by wild Rattus spp. in Northern Vietnam.

To examine the prevalence of human pathogens carried by rats in urban areas in Hanoi and Hai Phong, Vietnam, we live-trapped 100 rats in January 2011 and screened them for a panel of bacteria and viruses. Antibodies against Leptospira interrogans (22·0%), Seoul virus (14·0%) and rat hepatitis E virus (23·0%) were detected in rats, but antibodies against Yersinia pestis were not detected. Antibodies against L. interrogans and Seoul virus were found only in adult rats. In contrast, antibodies to rat hepatitis E virus were also found in juvenile and sub-adult rats, indicating that the transmission mode of rat hepatitis E virus is different from that of L. interrogans and Seoul virus. Moreover, phylogenetic analyses of the S and M segments of Seoul viruses found in Rattus norvegicus showed that Seoul viruses from Hai Phong and Hanoi formed different clades. Human exposure to these pathogens has become a significant public health concern.

Pneumococcal surface protein A family types of Streptococcus pneumoniae from community-acquired pneumonia patients in Japan.

We assessed pneumococcal surface protein A (PspA) family types of 141 isolates of Streptococcus pneumoniae from community-acquired pneumonia patients in Japan. Families 1 and 2 were expressed in 78 (55.3%) and 58 (41.1%) isolates, respectively. Five isolates were not typed either as family 1 or 2. PspA family types were not associated with age, sex, or pneumonia severity. Penicillin-resistant S. pneumoniae was more likely to belong to family 2 whereas organisms highly resistant to erythromycin and positive for ermB were more prevalent in family 1. The association of PspA type with antimicrobial resistance was possibly affected by prevalent serotypes or resistance clones. It would therefore be necessary to include both family 1 and 2 proteins in a PspA-containing vaccine to cover the major PspA families and to reduce antimicrobial resistance.

Killing of human Herpes virus 6-infected cells by lymphocytes cultured with interleukin-2 or -12.

BACKGROUND: Human Herpes virus 6 (HHV-6) is a causative agent of exanthema subitum and replicates mainly in lymphocytes. The aim of present study was to investigate cytotoxicity against HHV-6-infected cells by cord blood mononuclear cells (CBMC) and adult peripheral blood mononuclear cells (PBMC). METHODS: Human herpes virus 6-infected and -uninfected lymphocytes were used as target cells. Killing of target cells by CBMC and PBMC was investigated by the chromium release cytotoxicity assay. RESULTS: Freshly isolated CBMC and PBMC did not lyse HHV-6-infected and -uninfected cells. When CBMC and PBMC were cultured with interleukin (IL)-2, HHV-6-infected cells were significantly lysed compared with uninfected cells. Deletion of CD16+ cells by treatment of effector cells with anti-Leu-11b (CD16) antibody with complement reduced cytotoxicity against HHV-6-infected cells and T lymphocyte-rich cells did not lyse HHV-6-infected cells. Treatment of effector cells with anti-Fas ligand antibody and treatment of HHV-6-infected cells with anti-Fas antibody reduced cytotoxicity against HHV-6-infected cells. DNA fragmentation was detected in the supernatant from HHV-6-infected cells cultured with IL-2-activated lymphocytes. Culture of CBMC and PBMC with IL-12 also enhanced cytotoxicity against HHV-6-infected cells. CONCLUSIONS: These data suggest that lymphocytes cultured with IL-2 or IL-12 mediate killing against HHV-6-infected cells and killing of HHV-6-infected cells was through apoptosis. Fas-Fas ligand interaction is one pathway by which HHV-6-infected cells are killed. Killing of HHV-6-infected cells by NK cells activated by cytokines may play a role in the recovery from HHV-6 infection in vitro.