Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-21 (of 21 Records) |
Query Trace: Zeidner N [original query] |
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Occurrence of tuberculosis among people exposed to cattle in Bangladesh
Sarkar S , Haider N , Islam A , Hossain MB , Hossain K , Mafij Uddin MK , Rahman A , Ahmed SSU , Banu S , Rahim Z , Heffelfinger JD , Zeidner N . Vet Med Sci 2023 9 (4) 1923-1933 BACKGROUND: Tuberculosis (TB) has been an important public health concern in Bangladesh. The most common cause of human TB is Mycobacterium tuberculosis, while bovine TB is caused by Mycobacterium bovis. OBJECTIVE: The objective of this study was to determine the frequency of TB in individuals with occupational exposure to cattle and to detect Mycobacterium bovis among cattle in slaughterhouses in Bangladesh. METHODS: Between August and September 2015, an observational study was conducted in two government chest disease hospitals, one cattle market, and two slaughterhouses. Sputum samples were collected from individuals who met the criteria for suspected TB and had been exposed to cattle. Tissue samples were collected from cattle that had low body condition score(s). Both humans and cattle samples were screened for acid-fast bacilli (AFB) by Ziehl-Neelsen (Z-N) staining and cultured for Mycobacterium tuberculosis complex (MTC). Region of difference (RD) 9-based polymerase chain reaction (PCR) was also performed to identify Mycobacterium spp. We also conducted Spoligotyping to identify the specific strain of Mycobacterium spp. RESULTS: Sputum was collected from a total of 412 humans. The median age of human participants was 35 (IQR: 25-50) years. Twenty-five (6%) human sputum specimens were positive for AFB, and 44 (11%) were positive for MTC by subsequent culture. All (N = 44) culture-positive isolates were confirmed as Mycobacterium tuberculosis by RD9 PCR. Besides, 10% of cattle workers were infected with Mycobacterium tuberculosis in the cattle market. Of all TB (caused by Mycobacterium tuberculosis) infected individuals, 6.8% of individuals were resistant to one or two anti-TB drugs. The majority of the sampled cattle (67%) were indigenous breeds. No Mycobacterium bovis was detected in cattle. CONCLUSIONS: We did not detect any TB cases caused by Mycobacterium bovis in humans during the study. However, we detected TB cases caused by Mycobacterium tuberculosis in all humans, including cattle market workers. |
Mosquitoes of northwestern Uganda
Mutebi JP , Crabtree MB , Kading RC , Powers AM , Ledermann JP , Mossel EC , Zeidner N , Lutwama JJ , Miller BR . J Med Entomol 2018 55 (3) 587-599 Despite evidence of arbovirus activity in northwestern Uganda (West Nile Sub-region), there is very limited information on the mosquito fauna of this region. The only published study reported 52 mosquito species in northwestern Uganda but this study took place in 1950 and the information has not been updated for more than 60 yr. In January and June 2011, CO2 baited-light traps were used to collect 49,231 mosquitoes from four different locations, Paraa (9,487), Chobe (20,025), Sunguru (759), and Rhino Camp (18,960). Overall, 72 mosquito species representing 11 genera were collected. The largest number of distinct species was collected at Chobe (43 species), followed by Paraa (40), Sunguru (34), and Rhino Camp (25). Only eight of the 72 species (11.1%) were collected from all four sites: Aedes (Stegomyia) aegypti formosus (Walker), Anopheles (Cellia) funestus group, Culex (Culex) decens group, Cx. (Culex) neavei Theobald, Cx. (Culex) univittatus Theobald, Cx. (Culiciomyia) cinereus Theobald, Cx. (Oculeomyia) poicilipes (Theobald), and Mansonia (Mansonoides) uniformis (Theobald). Fifty-four species were detected in northwestern Uganda for the first time; however, these species have been detected elsewhere in Uganda and do not represent new introductions to the country. Thirty-three species collected during this study have previously been implicated in the transmission of arboviruses of public health importance. |
Biosecurity conditions in small commercial chicken farms, Bangladesh 2011-2012
Rimi NA , Sultana R , Muhsina M , Uddin B , Haider N , Nahar N , Zeidner N , Sturm-Ramirez K , Luby SP . Ecohealth 2017 14 (2) 244-258 In Bangladesh, highly pathogenic avian influenza H5N1 is endemic in poultry. This study aimed to understand the biosecurity conditions and farmers' perception of avian influenza biosecurity in Bangladeshi small commercial chicken farms. During 2011-2012, we conducted observations, in-depth interviews and group discussions with poultry farmers in 16 farms and in-depth interviews with seven local feed vendors from two districts. None of the farms were completely segregated from people, backyard poultry, other animals, households, other poultry farms or large trees. Wild birds and rodents accessed the farms for poultry feed. Farmers usually did not allow the buyers to bring egg trays inside their sheds. Spraying disinfectant in the shed and removing feces were the only regular cleaning and disinfection activities observed. All farmers sold or used untreated feces as fish feed or fertilizer. Farmers were more concerned about Newcastle disease and infectious bursal disease than about avian influenza. Farmers' understanding about biosecurity and avian influenza was influenced by local vendors. While we seldom observed flock segregation, some farmers used measures that involved additional cost or effort to protect their flocks. These farmers could be motivated by interventions to protect their investment from diseases they consider harmful. Future interventions could explore the feasibility and effectiveness of low-cost alternative biosecurity measures. |
An epidemiological study of avian influenza A (H5) virus in nomadic ducks and their raising practices in northeastern Bangladesh, 2011-2012
Sarkar S , Khan SU , Mikolon A , Rahman MZ , Abedin J , Zeidner N , Sturm-Ramirez K , Luby SP . Influenza Other Respir Viruses 2016 11 (3) 275-282 BACKGROUND: In Bangladesh nomadic duck flocks are groups of domestic ducks reared for egg production that are moved to access feeding sites beyond their owners' village boundaries and are housed overnight in portable enclosures in scavenging areas. The objectives of this study were to measure the prevalence of influenza A virus RNA and H5-specific antibodies in nomadic ducks and to characterize nomadic duck raising practices in northeastern Bangladesh. METHODS: We tested duck egg yolk specimens by competitive ELISA to detect antibodies against avian influenza A (H5) and environmental fecal samples by real time reverse transcription polymerase chain reaction (rRT-PCR) to detect influenza A virus RNA and H5 subtype. RESULTS: The median age of the ducks was 24 months (range: 8-36 months) and the median flock size was 300 ducks (range: 105-1,100). Of 1,860 egg yolk samples, 556 (30%, 95% confidence interval (CI): 28-32) were positive for antibodies against H5 and 58 flocks (94%) had at least one egg with H5 specific antibodies. Of 496 fecal samples, 121 (24%, 95% CI: 22-29) had detectable influenza A RNA. Thirty-three flocks (53%) had at least one fecal sample positive for influenza A RNA. CONCLUSIONS: Nomadic ducks in Bangladesh are commonly infected with avian influenza A (H5) virus and may serve as a bridging host for transmission of avian influenza A (H5) virus or other avian influenza A viruses subtypes between wild waterfowl, backyard poultry, and humans in Bangladesh. |
Raising backyard poultry in rural Bangladesh: Financial and nutritional benefits, but persistent risky practices
Shanta IS , Hasnat MA , Zeidner N , Gurley ES , Azziz-Baumgartner E , Sharker MA , Hossain K , Khan SU , Haider N , Bhuyan AA , Hossain MA , Luby SP . Transbound Emerg Dis 2016 64 (5) 1454-1464 Poultry is commonly raised by households in rural Bangladesh. In 2007, the Government of Bangladesh began a mass media campaign to disseminate 10 recommended precautions to prevent transmission of H5N1 from poultry to humans. This longitudinal study explored the contribution of backyard poultry on household economy and nutrition and compared poultry-raising practices to government recommendations. From 2009 to 2012, we enrolled a nationally representative sample of 2489 primary backyard poultry raisers from 115 rural villages selected by probability proportional to population size. Researchers interviewed the raisers to collect data on poultry-raising practices. They followed the raisers for 2-12 months to collect data on household income and nutrition from poultry. Income from backyard poultry flocks accounted for 2.8% of monthly household income. Return on annual investment (ROI) per flock was 480%. Yearly, median family consumption of eggs was one-fifth of the total produced eggs and three poultry from their own flock. Respondents' reported practices conflicted with government recommendations. Sixty per cent of raisers had never heard of avian influenza or 'bird flu'. Among the respondents, 85% handled sick poultry or poultry that died due to illness, and 49% slaughtered or defeathered sick poultry. In 37% of households, children touched poultry. Fifty-eight per cent never washed their hands with soap after handling poultry, while <1% covered their nose and mouth with a cloth when handling poultry. Only 3% reported poultry illness and deaths to local authorities. These reported practices did not improve during the study period. Raising backyard poultry in rural Bangladesh provides important income and nutrition with an excellent ROI. Government recommendations to reduce the risk of avian influenza transmission did not impact the behaviour of poultry producers. Further research should prioritize developing interventions that simultaneously reduce the risk of avian influenza transmission and increase productivity of backyard poultry. |
Transgene expression in tick cells using Agrobacterium tumefaciens.
Machado-Ferreira E , Balsemao-Pires E , Dietrich G , Hojgaard A , Vizzoni VF , Scoles G , Bell-Sakyi L , Piesman J , Zeidner NS , Soares CA . Exp Appl Acarol 2015 67 (2) 269-87 Ticks transmit infectious agents to humans and other animals. Genetic manipulation of vectors like ticks could enhance the development of alternative disease control strategies. Transgene expression using the phytopathogen Agrobacterium tumefaciens has been shown to promote the genetic modification of non-plant cells. In the present work we developed T-DNA constructs for A. tumefaciens to mediate transgene expression in HeLa cells as well as Rhipicephalus microplus tick cells. Translational fusions eGfp:eGfp or Salp15:eGfp, including the enhanced-green fluorescent protein and the Ixodes scapularis salivary factor SALP15 genes, were constructed using the CaMV 35S (cauliflower mosaic virus) promoter, "PBm" tick promoter (R. microplus pyrethroid metabolizing esterase gene) or the Simian Virus SV40 promoter. Confocal microscopy, RT-PCR and Western-blot assays demonstrated transgene(s) expression in both cell lines. Transgene expression was also achieved in vivo, in both R. microplus and I. scapularis larvae utilizing a soaking method including the A. tumefaciens donor cells and confirmed by nested-RT-PCR showing eGfp or Salp15 poly-A-mRNA(s). This strategy opens up a new avenue to express exogenous genes in ticks and represents a potential breakthrough for the study of tick-host pathophysiology. |
Unusually high mortality in waterfowl caused by highly pathogenic avian influenza A(H5N1) in Bangladesh
Haider N , Sturm-Ramirez K , Khan SU , Rahman MZ , Sarkar S , Poh MK , Shivaprasad HL , Kalam MA , Paul SK , Karmakar PC , Balish A , Chakraborty A , Mamun AA , Mikolon AB , Davis CT , Rahman M , Donis RO , Heffelfinger JD , Luby SP , Zeidner N . Transbound Emerg Dis 2015 64 (1) 144-156 Mortality in ducks and geese caused by highly pathogenic avian influenza A(H5N1) infection had not been previously identified in Bangladesh. In June-July 2011, we investigated mortality in ducks, geese and chickens with suspected H5N1 infection in a north-eastern district of the country to identify the aetiologic agent and extent of the outbreak and identify possible associated human infections. We surveyed households and farms with affected poultry flocks in six villages in Netrokona district and collected cloacal and oropharyngeal swabs from sick birds and tissue samples from dead poultry. We conducted a survey in three of these villages to identify suspected human influenza-like illness cases and collected nasopharyngeal and throat swabs. We tested all swabs by real-time RT-PCR, sequenced cultured viruses, and examined tissue samples by histopathology and immunohistochemistry to detect and characterize influenza virus infection. In the six villages, among the 240 surveyed households and 11 small-scale farms, 61% (1789/2930) of chickens, 47% (4816/10 184) of ducks and 73% (358/493) of geese died within 14 days preceding the investigation. Of 70 sick poultry swabbed, 80% (56/70) had detectable RNA for influenza A/H5, including 89% (49/55) of ducks, 40% (2/5) of geese and 50% (5/10) of chickens. We isolated virus from six of 25 samples; sequence analysis of the hemagglutinin and neuraminidase gene of these six isolates indicated clade 2.3.2.1a of H5N1 virus. Histopathological changes and immunohistochemistry staining of avian influenza viral antigens were recognized in the brain, pancreas and intestines of ducks and chickens. We identified ten human cases showing signs compatible with influenza-like illness; four were positive for influenza A/H3; however, none were positive for influenza A/H5. The recently introduced H5N1 clade 2.3.2.1a virus caused unusually high mortality in ducks and geese. Heightened surveillance in poultry is warranted to guide appropriate diagnostic testing and detect novel influenza strains. |
Reservoir targeted vaccine against Borrelia burgdorferi: a new strategy to prevent Lyme disease transmission
Richer LM , Brisson D , Melo R , Ostfeld RS , Zeidner N , Gomes-Solecki M . J Infect Dis 2014 209 (12) 1972-80 A high prevalence of infection with Borrelia burgdorferi in ixodid ticks is correlated with a high incidence of Lyme disease. The transmission of B. burgdorferi to humans can be disrupted by targeting 2 key elements in its enzootic cycle: the reservoir host and the tick vector. In a prospective 5-year field trial, we show that oral vaccination of wild white-footed mice resulted in outer surface protein A-specific seropositivity that led to reductions of 23% and 76% in the nymphal infection prevalence in a cumulative, time-dependent manner (2 and 5 years, respectively), whereas the proportion of infected ticks recovered from control plots varied randomly over time. Significant decreases in tick infection prevalence were observed within 3 years of vaccine deployment. Implementation of such a long-term public health measure could substantially reduce the risk of human exposure to Lyme disease. |
Identification and epidemiology of a rare HoBi-like pestivirus strain in Bangladesh.
Haider N , Rahman MS , Khan SU , Mikolon A , Gurley ES , Osmani MG , Shanta IS , Paul SK , Macfarlane-Berry L , Islam A , Desmond J , Epstein JH , Daszak P , Azim T , Luby SP , Zeidner N , Rahman MZ . Transbound Emerg Dis 2014 61 (3) 193-8 The genus pestivirus of the family flaviviridae consists of four recognized species: bovine viral diarrhoea virus 1 (BVDV-1), bovine viral diarrhoea virus 2 (BVDV-2), classical swine fever virus and border disease virus. A new putative pestivirus species tentatively named as either 'HoBi-like pestivirus' or BVDV-3 has recently been identified in Brazil, Italy and Thailand. Despite reports of serological evidence of BVDV in Bangladesh, the types of the virus circulating in cattle have not been identified. We conducted surveillance in cattle from May 2009 to August 2010 in three government veterinary hospitals to characterize BVDV in cattle of Bangladesh. We tested serum for BVDV using an antigen-capture ELISA. Of 638 cattle samples, 3% (16/638) tested positive for BVDV antigen. The ELISA-positive samples were selected for further molecular detection and characterization of BVDV. Molecular analysis of the partial 5' untranslated region (UTR) nucleotide sequences of BVDV-positive samples identified the rare HoBi-like pestivirus or BVDV-3 virus circulating in cattle of Bangladesh. The identification of this rare HoBi-like pestivirus or BVDV-3 strain in Bangladesh warrants further surveillance to evaluate its impact on livestock production. |
Sunguru virus: a novel virus in the family Rhabdoviridae isolated from a chicken in north-western Uganda.
Ledermann JP , Zeidner N , Borland EM , Mutebi JP , Lanciotti RS , Miller BR , Lutwama JJ , Tendo JM , Andama V , Powers AM . J Gen Virol 2014 95 1436-1443 Sunguru virus (SUNV), a novel virus belonging to the highly diverse Rhabdoviridae family, was isolated from a domestic chicken in the district of Arua, Uganda in 2011. This is the first documented isolation of a rhabdovirus from a chicken. SUNV is related to, but distinct from, Boteke virus and other members of the unclassified Sandjimba group. The genome is 11,056 kb in length and contains the five core rhabdovirus genes plus an additional C gene (within the open reading frame of the phosphoprotein gene) and a small hydrophobic protein (between the matrix and glycoprotein genes). Inoculation of vertebrate cells resulted in significant growth, with a peak titer of 7.8 log10 PFU/mL observed in baby hamster kidney cells. Little to no growth was observed in invertebrate cells and in live mosquitoes, with Anopheles gambiae mosquitoes demonstrating a 47.4% infection rate in the body but no dissemination to the salivary glands; this suggests that this novel virus is not arthropod-borne like some other members of the family Rhabdoviridae. |
Investigating a crow die-off in January-February 2011 during the introduction of a new clade of highly pathogenic avian influenza virus H5N1 into Bangladesh
Khan SU , Berman L , Haider N , Gerloff N , Rahman MZ , Shu B , Rahman M , Dey TK , Davis TC , Das BC , Balish A , Islam A , Teifke JP , Zeidner N , Lindstrom S , Klimov A , Donis RO , Luby SP , Shivaprasad HL , Mikolon AB . Arch Virol 2014 159 (3) 509-18 We investigated unusual crow mortality in Bangladesh during January-February 2011 at two sites. Crows of two species, Corvus splendens and C. macrorhynchos, were found sick and dead during the outbreaks. In selected crow roosts, morbidity was ~1 % and mortality was ~4 % during the investigation. Highly pathogenic avian influenza virus H5N1 clade 2.3.2.1 was isolated from dead crows. All isolates were closely related to A/duck/India/02CA10/2011 (H5N1) with 99.8 % and A/crow/Bangladesh/11rs1984-15/2011 (H5N1) virus with 99 % nucleotide sequence identity in their HA genes. The phylogenetic cluster of Bangladesh viruses suggested a common ancestor with viruses found in poultry from India, Myanmar and Nepal. Histopathological changes and immunohistochemistry staining in brain, pancreas, liver, heart, kidney, bursa of Fabricius, rectum, and cloaca were consistent with influenza virus infection. Through our limited investigation in domesticated birds near the crow roosts, we did not identify any samples that tested positive for influenza virus A/H5N1. However, environmental samples collected from live-bird markets near an outbreak site during the month of the outbreaks tested very weakly positive for influenza virus A/H5N1 in clade 2.3.2.1-specific rRT-PCR. Continuation of surveillance in wild and domestic birds may identify evolution of new avian influenza virus and associated public-health risks. |
Multiple reassortment events among highly pathogenic avian influenza A(H5N1) viruses detected in Bangladesh.
Gerloff NA , Khan SU , Balish A , Shanta IS , Simpson N , Berman L , Haider N , Poh MK , Islam A , Gurley E , Hasnat MA , Dey T , Shu B , Emery S , Lindstrom S , Haque A , Klimov A , Villanueva J , Rahman M , Azziz-Baumgartner E , Ziaur Rahman M , Luby SP , Zeidner N , Donis RO , Sturm-Ramirez K , Davis CT . Virology 2014 450-451 297-307 In Bangladesh, little is known about the genomic composition and antigenicity of highly pathogenic avian influenza A(H5N1) viruses, their geographic distribution, temporal patterns, or gene flow within the avian host population. Forty highly pathogenic avian influenza A(H5N1) viruses isolated from humans and poultry in Bangladesh between 2008 and 2012 were analyzed by full genome sequencing and antigenic characterization. The analysis included viruses collected from avian hosts and environmental sampling in live bird markets, backyard poultry flocks, outbreak investigations in wild birds or poultry and from three human cases. Phylogenetic analysis indicated that the ancestors of these viruses reassorted (1) with other gene lineages of the same clade, (2) between different clades and (3) with low pathogenicity avian influenza A virus subtypes. Bayesian estimates of the time of most recent common ancestry, combined with geographic information, provided evidence of probable routes and timelines of virus spread into and out of Bangladesh. |
Immunization with Culex tarsalis mosquito salivary gland extract modulates West Nile virus infection and disease in mice
Machain-Williams C , Reagan K , Wang T , Zeidner NS , Blair CD . Viral Immunol 2013 26 (1) 84-92 Mosquito salivary proteins inoculated during blood feeding modulate the host immune response, which can contribute to the pathogenesis of viruses transmitted by mosquito bites. Previous studies with mosquito bite-naive mice indicated that exposure to arthropod salivary proteins resulted in a shift toward a Th2-type immune response in flavivirus-susceptible mice but not flavivirus-resistant animals. In the study presented here, we tested the hypothesis that immunization with high doses of Culex tarsalis salivary gland extracts (SGE) with an adjuvant would prevent Th2 polarization after mosquito bite and enhance resistance to mosquito-transmitted West Nile virus (WNV). Our results indicate that mice immunized with Cx. tarsalis SGE produced increased levels of Th1-type cytokines (IFNgamma and TNFalpha) after challenge with mosquito-transmitted WNV and exhibited both a delay in infection of the central nervous system (CNS) and significantly lower WNV brain titers compared to mock-immunized mice. Moreover, mortality was significantly reduced in the SGE-immunized mice, as none of these mice died, compared to mortality of 37.5% of mock-vaccinated mice by 8 days after infected mosquito bite. These results suggest that development of a mosquito salivary protein vaccine might be a strategy to control arthropod-borne viral pathogens such as WNV. |
A prevalent alpha-proteobacterium Paracoccus sp. in a population of the Cayenne ticks (Amblyomma cajennense) from Rio de Janeiro, Brazil
Machado-Ferreira E , Piesman J , Zeidner NS , Soares CA . Genet Mol Biol 2012 35 (4) 862-7 As Rocky Mountain Spotted Fever is the most common tick-borne disease in South America, the presence of Rickettsia sp. in Amblyomma ticks is a possible indication of its endemicity in certain geographic regions. In the present work, bacterial DNA sequences related to Rickettsia amblyommii genes in A. dubitatum ticks, collected in the Brazilian state of Mato Grosso, were discovered. Simultaneously, Paracoccus sp. was detected in aproximately 77% of A. cajennense specimens collected in Rio de Janeiro, Brazil. This is the first report of Paracoccus sp. infection in a specific tick population, and raises the possibility of these bacteria being maintained and/or transmitted by ticks. Whether Paracoccus sp. represents another group of pathogenic Rhodobacteraceae or simply plays a role in A. cajennense physiology, is unknown. The data also demonstrate that the rickettsial 16S rRNA specific primers used for Rickettsia spp. screening can also detect Paracoccus alpha-proteobacteria infection in biological samples. Hence, a PCR-RFLP strategy is presented to distinguish between these two groups of bacteria. |
Immunization with adenoviral-vectored tick salivary gland proteins (SALPs) in a murine model of Lyme borreliosis
Ullmann AJ , Dolan MC , Sackal CA , Fikrig E , Piesman J , Zeidner NS . Ticks Tick Borne Dis 2012 4 160-3 Prior exposure of vertebrate hosts to tick salivary proteins can induce specific immunity to tick infestation, as well as affording protection against tick-transmitted Borrelia burgdorferi infection in the mammalian host. Vaccination using an adenovirus expression system to deliver 4 tick salivary proteins (Ad-Salps) derived from Ixodes scapularis, Salp15, Salp25A, Salp25D, and Isac, was explored. Results indicate that vaccination with tick salivary proteins in an adenoviral vector can be used to modulate a Th1 response in the host and partially control spirochete load in immunized mice after infected tick challenge. |
Elimination of Borrelia burgdorferi and Anaplasma phagocytophilum in rodent reservoirs and Ixodes scapularis ticks using a doxycycline hyclate-laden bait
Dolan MC , Schulze TL , Jordan RA , Dietrich G , Schulze CJ , Hojgaard A , Ullmann AJ , Sackal C , Zeidner NS , Piesman J . Am J Trop Med Hyg 2011 85 (6) 1114-20 A field trial was conducted in a Lyme disease-endemic area of New Jersey to determine the efficacy of a doxycyline hyclate rodent bait to prophylactically protect and cure small-mammal reservoirs and reduce infection rates in questing Ixodes scapularis ticks for Borrelia burgdorferi and Anaplasma phagocytophilum. The doxycycline-laden bait was formulated at a concentration of 500 mg/kg and delivered during the immature tick feeding season in rodent-targeted bait boxes. The percentage of infected small mammals recovered from treated areas after 2 years of treatment was reduced by 86.9% for B. burgdorferi and 74% for A. phagocytophilum. Infection rates in questing nymphal ticks for both B. burgdorferi and A. phagocytophilum were reduced by 94.3% and 92%, respectively. Results from this study indicate that doxycycline-impregnated bait is an effective means of reducing infection rates for B. burgdorferi and A. phagocytophilum in both rodent reservoirs and questing I. scapularis ticks. |
Association of human immune response to Aedes aegypti salivary proteins with dengue disease severity
Machain-Williams C , Mammen MP Jr , Zeidner NS , Beaty BJ , Prenni JE , Nisalak A , Blair CD . Parasite Immunol 2011 34 (1) 15-22 Dengue viruses (DENV; family Flaviviridae, genus Flavivirus) are transmitted by Aedes aegypti mosquitoes and can cause dengue fever (DF), a relatively benign disease, or more severe dengue haemorrhagic fever (DHF). Arthropod saliva contains proteins delivered into the bite wound that can modulate the host haemostatic and immune responses to facilitate the intake of a blood meal. The potential effects on DENV infection of previous exposure to Ae. aegypti salivary proteins has not been investigated. We collected Ae. aegypti saliva, concentrated the proteins, and fractionated them by non-denaturing polyacrylamide gel electrophoresis (PAGE). By use of immunoblots we analysed reactivity with the mosquito salivary proteins (MSP) of sera from 96 Thai children diagnosed with secondary DENV infections leading either to DF or DHF, or with no DENV infection, and found that different proportions of each patient group had serum antibodies reactive to specific Ae. aegypti salivary proteins. Our results suggest that prior exposure to MSP might play a role in the outcome of DENV infection in humans. |
Experimental infection of Swiss Webster mice with four rat bartonella strains: host specificity, bacteremia kinetics, dose dependent response, and histopathology
Colton L , Zeidner N , Kosoy MY . Comp Immunol Microbiol Infect Dis 2011 34 (6) 465-73 Groups of Swiss Webster outbred mice were each inoculated with one of four bartonella strains originally isolated from Rattus spp. at doses ranging from 10(1) to 10(7) bacteria per mouse. One strain, Rn1691yn (Bartonella coopersplainensis-like), infected mice and produced bacteremias at levels up to 10(5) bacteria/ml of blood and from 3 to 8 weeks duration. A dose dependent response was also observed with differing proportions of mice bacteremic following inoculation at different doses. In addition weeks-to-months long lags in bacteremia manifestation occurred following lower dose exposures. The possibility of bacterial transmission from bacteremic mice to uninfected cagemates was assessed and no naive mice became infected from contacts with infected mice. Finally, a subset of bacteremic mice inoculated with high doses of Rn1691yn were examined histopathologically and multifocal, granulomatous lesions were detected in both liver and kidneys. The host specificity and infectivity of the strains is discussed in relation to their potential for zoonotic transmission to incidental hosts. |
Epidemiologic and clinical aspects of a Rift Valley fever outbreak in humans in Tanzania, 2007
Mohamed M , Mosha F , Mghamba J , Zaki SR , Shieh WJ , Paweska J , Omulo S , Gikundi S , Mmbuji P , Bloland P , Zeidner N , Kalinga R , Breiman RF , Njenga MK . Am J Trop Med Hyg 2010 83 22-7 In January 2007, an outbreak of Rift Valley fever (RVF) was detected among humans in northern Tanzania districts. By the end of the outbreak in June, 2007, 511 suspect RVF cases had been recorded from 10 of the 21 regions of Tanzania, with laboratory confirmation of 186 cases and another 123 probable cases. All confirmed RVF cases were located in the north-central and southern regions of the country, with an eventual fatality rate of 28.2% (N = 144). All suspected cases had fever; 89% had encephalopathy, 10% hemorrhage, and 3% retinopathy. A total of 169 (55%) of the 309 confirmed or probable cases were also positive for malaria as detected by peripheral blood smear. In a cohort of 20 RVF cases with known outcome that were also positive for human immunodeficiency virus, 15 (75%) died. Contact with sick animals and animal products, including blood, meat, and milk, were identified as major risk factors of acquiring RVF. |
Human isolates of Bartonella tamiae induce pathology in experimentally inoculated immunocompetent mice
Colton L , Zeidner N , Lynch T , Kosoy MY . BMC Infect Dis 2010 10 229 BACKGROUND: Bartonella tamiae, a newly described bacterial species, was isolated from the blood of three hospitalized patients in Thailand. These patients presented with headache, myalgia, anemia, and mild liver function abnormalities. Since B. tamiae was presumed to be the cause of their illness, these isolates were inoculated into immunocompetent mice to determine their relative pathogenicity in inducing manifestations of disease and pathology similar to that observed in humans. METHODS: Three groups of four Swiss Webster female mice aged 15-18 months were each inoculated with 10(6-7) colony forming units of one of three B. tamiae isolates [Th239, Th307, and Th339]. A mouse from each experimental group was sampled at 3, 4, 5 and 6 weeks post-inoculation. Two saline inoculated age-matched controls were included in the study. Samples collected at necropsy were evaluated for the presence of B. tamiae DNA, and tissues were formalin-fixed, stained with hematoxylin and eosin, and examined for histopathology. RESULTS: Following inoculation with B. tamiae, mice developed ulcerative skin lesions and subcutaneous masses on the lateral thorax, as well as axillary and inguinal lymphadenopathy. B. tamiae DNA was found in subcutaneous masses, lymph node, and liver of inoculated mice. Histopathological changes were observed in tissues of inoculated mice, and severity of lesions correlated with the isolate inoculated, with the most severe pathology induced by B. tamiae Th239. Mice inoculated with Th239 and Th339 demonstrated myocarditis, lymphadenitis with associated vascular necrosis, and granulomatous hepatitis and nephritis with associated hepatocellular and renal necrosis. Mice inoculated with Th307 developed a deep dermatitis and granulomas within the kidneys. CONCLUSIONS: The three isolates of B. tamiae evaluated in this study induce disease in immunocompetent Swiss Webster mice up to 6 weeks after inoculation. The human patients from whom these isolates were obtained had clinical presentations consistent with the multi-organ pathology observed in mice in this study. This mouse model for B. tamiae induced disease not only strengthens the causal link between this pathogen and clinical illness in humans, but provides a model to further study the pathological processes induced by these bacteria. |
Molecular identification of Salp15, a key salivary gland protein in the transmission of lyme disease spirochetes, from Ixodes persulcatus and Ixodes pacificus (Acari: Ixodidae)
Hojgaard A , Biketov SF , Shtannikov AV , Zeidner NS , Piesman J . J Med Entomol 2009 46 (6) 1458-63 Salp15 is a multifunctional protein, vital to the tick in its need to obtain vertebrate host blood without stimulating a host inflammatory and immune response. The Salpl5 protein from both Ixodes scapularis Say and Ixodes ricinus (L.), the principal vectors of the Lyme disease spirochete in eastern North America and Europe, respectively, have been well characterized and found to bind the murine CD4 receptor, DC-SIGN, and the OspC protein of Borrelia burgdorferi. In the current study, we characterized the full salp15 gene in Ixodes pacificus Cooley & Kohls and Ixodes persulcatus Schulze, the principal vectors of Lyme disease spirochetes in western North America and Asia, respectively. In comparing the Salp15 protein of all four principal vector ticks of public health importance for the transmission of Lyme disease spirochetes, we find the 53 C-terminal amino acids to have a high degree of similarity. There are at least three clades in the tree of Salp15 and its homologues, probably representing a multigene family. |
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