Multiple Orientia clusters and Th1-skewed chemokine profile: a cross-sectional study in patients with scrub typhus from Nepal.

OBJECTIVES: Scrub typhus is an emerging infectious disease in Asia caused by Orientia tsutsugamushi (Ot). From Nepal, only scant data on the genetic epidemiology of this agent is available, and determinants of immunoregulation are poorly understood. METHODS: Patients (n = 238) referred to the National Public Health Laboratory (Kathmandu, Nepal) from all over Nepal for suspected scrub typhus were enrolled upon positive immunoglobulin (Ig)M testing between July and October 2015. From Ot 16S and 47 kD polymerase chain reaction (PCR)-positive samples, the variable domain I of the 56 kD gene was sequenced and phylogenetically analyzed. T helper (Th) cell-associated cytokines (n = 13) and chemokines (n = 12) were quantified by multiplex bead arrays. RESULTS: In 93/238 (39.1%) IgM-positive samples, Ot DNA was detected by quantitative PCR. Phylogenetic analysis of 56 kD sequences revealed seven distinct clusters, six of them with high homologies to strains detected in other countries. The Th1-related cytokines interferon-γ and C-X-C motif chemokine ligand 10 were strongly upregulated and correlated with bacteremia, while levels of Th2-associated chemokines were reduced. Bacteremia also correlated with concentrations of interleukin (IL)-6 and IL-10 but not tumor necrosis factor-α. CONCLUSION: We identified a considerable genetic heterogeneity of human-pathogenic Ot strains circulating in Nepal. Acute Nepalese scrub typhus patients showed strong Th1 but impaired Th2 responses, especially on the chemokine level.

Changing epidemiology and antimicrobial resistance in Vibrio cholerae: AMR surveillance findings (2006-2016) from Nepal.

BACKGROUND: In Nepal, cases of Cholera occur annually either as sporadic or as outbreaks claiming the lives of many in rural areas. The present study is a laboratory based surveillance which aims to analyze the changing epidemiology and antimicrobial susceptibility trend of V. cholerae strains isolated or referred to National Public Health Laboratory (NPHL) over a period of 11 years (2006-2016). METHODS: Specimens of fresh stool /rectal swab either received at sentinel sites or NPHL were processed following standard microbiological techniques. Suspected colonies on selective medium were identified using routine biochemical tests and confirmed by serotyping. Antimicrobial susceptibility testing was performed following Kirby Baeur disc diffusion method. RESULTS: Of the 836 confirmed isolates, 87% (728/836) were V.cholerae O1 Ogawa,12% (103/836) were V.cholerae O1 Inaba and only 6 isolates were V.cholerae O1 Hikojima. In 2006 all the Vibrio isolates were of Inaba serotype, followed by all 3 serotypes during 2007.During 2008-2014 only Ogawa serotype was isolated while few cases of Inaba again surfaced in 2015. Resistance to ampicillin decreased from 93% in 2006 to 18% by 2010 and again raised to 100% by 2016.Cotrimoxazole resistance remained at constant range (77-100%).Nalidixic acid resistance was 100% since 2006.Ciprofloxacin and tetracycline resistance emerged in 2007, reached a peak during 2010-2012 and declined to 0 by 2016.Susceptibility to Furazolidone has re-emerged.63.6% of the isolates were Multi drug resistant. CONCLUSION: With changing epidemiology and antibiogram of V.cholerae in Nepal, the present study reflects the importance of continuous monitoring, which could be used by policy makers and health professionals for better management of outbreaks. Decline in tetracycline and ciprofloxacin resistance along with emerging sensitivity to furazolidone shows that these drugs could make an effective comeback in future.

Outbreak Investigation Following the 2015 Earthquake Disaster in Nepal.

BACKGROUND: Infectious disease outbreaks following natural disasters are reported in literature. Outbreaks were documented following natural disasters in many countries including Haiti. Such possibility following 2015 Nepal earthquake was a public health concern. Risk factors needed evaluation by post-disaster outbreak investigation. Hence, present study was undertaken to investigate potentials for such outbreak and to generate evidence for public health intervention. METHODS: The study was conducted between April - May, 2015, with the cooperation of National Public Health Laboratory, Epidemiology and Disease Control Division, Nepal Health Research Council and the Chinese team. Rapid Response Teams visited earthquake affected districts and collected samples for analysis. Syndromic surveillance approach was followed. Samples were collected from syndromic patients under supervision. Those sick prior to earthquake or receiving treatment were excluded. Blood, stool and throat swab samples, as indicated, were collected. Drinking water and food samples including captured live mosquitoes from inhabited areas were obtained for study with the help of EDCD. Laboratory analysis was performed at the NPHL. RESULTS: Total samples were 360 (114 biological, 246 environmental). Salmonella spp. was detected in two and Varicella zoster in one blood sample. Influenza B virus was detected in one throat swab. Rota virus was detected in two, Shigella dysenteriae in one and Salmonella spp. in one stool sample. No pathogen detected in water or food samples. Mosquitoes tested negative for dengue virus. CONCLUSIONS: Post-earthquake outbreak investigated in disaster phase-2. Diarrheal, enteric fever pathogens and Influenza B virus were detected. Environmental samples tested negative for pathogens. Vigilance is necessary for other risk factors.