The American journal of tropical medicine and hygiene, Jan 23, 2018
The ongoing Zika pandemic has affected many countries that are common travel destinations. We ass... more The ongoing Zika pandemic has affected many countries that are common travel destinations. We assessed the willingness to receive a prophylactic Zika virus (ZIKV) vaccine, currently under development, among travelers to areas with reported autochthonous ZIKV transmission. We surveyed United States (U.S.) residents aged 18-44 years who had ever heard of ZIKV and planned to travel to Florida and/or Texas ( = 420) or a U.S. territory or foreign country ( = 415) in 2017, using a nationally representative internet panel. Travelers to Florida and/or Texas reported less concern about ZIKV infection than travelers to other destinations (27% versus 36%, = 0.01). Female gender, Hispanic ethnicity, discussing ZIKV with medical professionals, ZIKV risk perception, and self-efficacy for ZIKV prevention predicted concern about ZIKV infection in both groups. Travelers to Florida and/or Texas (43%) and other destinations (44%) were equally willing to receive a ZIKV vaccine. Hispanic ethnicity, disc...
The American journal of tropical medicine and hygiene, Jan 7, 2018
Limited data exist about U.S. travelers' knowledge, risk perceptions, and behaviors related t... more Limited data exist about U.S. travelers' knowledge, risk perceptions, and behaviors related to the Zika virus (ZIKV). Using an internet research panel, in March 2017, we surveyed 1,202 Americans in the continental United States and Puerto Rico who planned to travel to a Zika-affected country, state, or U.S. territory in 2017. We compared levels of knowledge and perceived risk of ZIKV, and intentions to practice ZIKV prevention behaviors across respondents from three regions: Puerto Rico, at-risk states, and other states. More than 80% of respondents correctly understood that a person could acquire ZIKV through a bite from an infected mosquito, and over 64% of respondents knew that a pregnant woman could pass the virus to her fetus. Less than half of the respondents from at-risk states and other states knew that ZIKV could be transmitted sexually, as compared with three-quarters of respondents from Puerto Rico. Compared with respondents from at-risk and other states, respondents ...
The American journal of tropical medicine and hygiene, Jan 2, 2017
Infestation with Sarcoptes scabiei var. hominis is a common human parasitic affliction endemic in... more Infestation with Sarcoptes scabiei var. hominis is a common human parasitic affliction endemic in tropical developing countries. Scabies is transmitted by close person-person contact, and outbreaks have been reported in reception centers for asylum seekers. Scabies presents clinically as extremely pruritic excoriated papules and linear burrows in the skin. This infestation predisposes to bacterial skin infections that can result in serious complications affecting the kidneys and possibly the heart. Treatment of individuals with scabies and their close contacts involves the use of antiparasitic agents. First-line treatment is topical 5% permethrin cream. Community mass drug administration, followed by active case finding with targeted treatment, is a promising approach that can reduce the prevalence of both scabies and bacterial skin infections. Organizations such as the International Alliance for the Control of Scabies are advocating for the development of integrated disease control...
The nucleotide sequences of the mglA and mglC genes of Salmonella typhimurium (St) LT2 have been ... more The nucleotide sequences of the mglA and mglC genes of Salmonella typhimurium (St) LT2 have been determined. The deduced amino acid (aa) sequences of MglA and MglC are 506 and 302 aa long with predicted molecular masses of 56,484 and 31,551 Da, respectively. The aa sequences of St MglA and MglC are homologous to the corresponding Mgl proteins of Escherichia coli, Haemophilus influenzae, Treponema pallidum and Mycoplasma genitalium. The order of the St mgl operon is mglBAC.
We have characterized a 5.2-kilobase (kb) putative transport related operon (tro) locus of Trepon... more We have characterized a 5.2-kilobase (kb) putative transport related operon (tro) locus of Treponema pallidum subsp. pallidum (Nichols strain) (Tp) encoding six proteins: TroA, TroB, TroC, TroD, TroR and Phosphoglycerate mutase (Pgm). Four of these gene products (TroA-TroD) are homologous to members of the ATP-Binding Cassette (ABC) superfamily of bacterial transport proteins. TroA (previously identified as Tromp1) has significant sequence similarity to a family of Gram-negative periplasmic substrate-binding proteins and to a family of streptococcal proteins that may have dual roles as substrate binding proteins and adhesins. TroB is homologous to the ATP-binding protein component, whereas TroC and TroD are related to the hydrophobic membrane protein components of ABC transport systems. TroR is similar to Gram-positive iron-activated repressor proteins (DesR, DtxR, IdeR, and SirR). The last open reading frame (ORF) of the tro operon encodes a protein that is highly homologous to the glycolytic pathway enzyme, Pgm. Primer extension results demonstrated that the tro operon is transcribed from a sigma 70-type promoter element. Northern analysis and reverse transcriptase-polymerase chain reactions provided evidence for the presence of a primary 1-kb troA transcript and a secondary, less abundant, troA-pgm transcript. The tro operon is flanked by a Holliday structure DNA helicase homolog (upstream) and two ORFs representing a purine nucleoside phosphorylase homolog and tpp15, a previously characterized gene encoding a membrane lipoprotein (downstream). The presence of a complex operon containing a putative ABC transport system and a DtxR homolog indicates a possible linkage between transport and gene regulation in Tp.
The American journal of tropical medicine and hygiene, Jan 2, 2015
Ebola virus disease (EVD) is a life-threatening zoonosis caused by infection with the Ebola virus... more Ebola virus disease (EVD) is a life-threatening zoonosis caused by infection with the Ebola virus. Since the first reported EVD outbreak in the Democratic Republic of the Congo, several small outbreaks have been reported in central Africa with about 2,400 cases occurring between 1976 and 2013. The 2013-2015 EVD outbreak in west Africa is the first documented outbreak in this region and the largest ever with over 27,000 cases and more than 11,000 deaths. Although EVD transmission rates have recently decreased in west Africa, this crisis continues to threaten global health and security, particularly since infected travelers could spread EVD to other resource-limited areas of the world. Because vaccines and drugs are not yet licensed for EVD, outbreak control is dependent on the use of non-pharmaceutical interventions (e.g., infection control practices, isolation of EVD cases, contact tracing with follow-up and quarantine, sanitary burial, health education). However, delays in diagnosi...
The American journal of tropical medicine and hygiene, Jan 13, 2015
Yaws is a neglected infectious disease that affects mostly children and adolescents living in poo... more Yaws is a neglected infectious disease that affects mostly children and adolescents living in poor, rural communities in humid, tropical areas of Africa, southeast Asia, and the Pacific Islands. The etiological agent of yaws, Treponema pallidum subspecies pertenue (T. pertenue), was discovered by Aldo Castellani in 1905 shortly after Schaudinn and Hoffmann discovered the etiological agent of syphilis, T. pallidum subspecies pallidum. The discovery of T. pertenue enabled the development of animal models and the identification of an effective antibiotic treatment (i.e., penicillin) for yaws. A World Health Organization (WHO) mass treatment campaign from 1952 to 1964 reduced the global burden of yaws by 95%, but failed to eradicate this disease. Today, 110 years after Castellani's discovery of T. pertenue, yaws is again targeted for eradication. Recent advances in the treatment and diagnosis of yaws improved the likelihood of success this time. However, several challenges must be o...
The etiology of bovine ulcerative mammary dermatitis (UMD) is poorly characterized. The goal of t... more The etiology of bovine ulcerative mammary dermatitis (UMD) is poorly characterized. The goal of this study was to genetically analyze spirochetes present in UMD lesions. DNA prepared from UMD lesion biopsies and from spirochetes cultured from the corresponding lesion biopsies was PCR amplified using primers for the 16S rDNA-tRNA(ile) intergenic spacer region (ISR) of Treponema 16S-23S rDNA. Analysis of cloned ISR amplicons from three cultivable UMD-associated spirochetes indicated that two isolates cluster closely with cultivable papillomatous digital dermatitis (PDD)-associated and human-associated Treponema phylotypes, while the remaining isolate is unique. Analysis of ISR amplicons from UMD lesion biopsies identified additional not-yet-cultivable Treponema phylotypes. Our results revealed the presence of a genetically diverse Treponema population in an UMD lesion.
The nucleotide sequence of the Treponema pallidum mcp2 gene was determined. mcp2 encodes a 45.8-k... more The nucleotide sequence of the Treponema pallidum mcp2 gene was determined. mcp2 encodes a 45.8-kDa protein whose deduced amino acid sequence has significant homology with the C-terminal region of bacterial methyl-accepting chemotaxis proteins (MCPs). The Mcp2 N terminus lacks the hydrophobic transmembrane regions present in most MCPs. An Mcp2 fusion protein was strongly reactive with antibody (HC23) to the highly conserved domain of MCPs and with rabbit syphilitic serum. Antibody HC23 reacted with six T. pallidum proteins, including a 45-kDa protein that may correspond to Mcp2. This protein was present in the aqueous phase from T. pallidum cells that were solubilized with Triton X-114 and phase partitioned.
A new medium that permits radiolabeling of freshly extracted cells of Treponema pallidum with [35... more A new medium that permits radiolabeling of freshly extracted cells of Treponema pallidum with [35S]methionine very efficiently has been devised. Although treponemes were not purified free of contaminating rabbit tissue, label was incorporated exclusively into treponemal protein in a linear manner for at least the first 16 h of in vitro incubation. Throughout this period, virtually a full complement of treponemal proteins was synthesized, based on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis comparison of the radiolabeled protein profile with the Coomassie blue-stained profile of gradient-purified treponemes. The radiolabeled protein profiles obtained with three pathogenic strains were very similar but not identical. Using solubilized treponemal extracts and a sensitive radioimmunoprecipitation procedure, we identified the protein antigens of T. pallidum that were recognized by immunoglobulin G antibodies in various rabbit and human syphilitic sera. A simple fractionat...
The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and... more The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10, and 1% survival were determined for representative serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay, L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent m...
The American journal of tropical medicine and hygiene, Jan 23, 2018
The ongoing Zika pandemic has affected many countries that are common travel destinations. We ass... more The ongoing Zika pandemic has affected many countries that are common travel destinations. We assessed the willingness to receive a prophylactic Zika virus (ZIKV) vaccine, currently under development, among travelers to areas with reported autochthonous ZIKV transmission. We surveyed United States (U.S.) residents aged 18-44 years who had ever heard of ZIKV and planned to travel to Florida and/or Texas ( = 420) or a U.S. territory or foreign country ( = 415) in 2017, using a nationally representative internet panel. Travelers to Florida and/or Texas reported less concern about ZIKV infection than travelers to other destinations (27% versus 36%, = 0.01). Female gender, Hispanic ethnicity, discussing ZIKV with medical professionals, ZIKV risk perception, and self-efficacy for ZIKV prevention predicted concern about ZIKV infection in both groups. Travelers to Florida and/or Texas (43%) and other destinations (44%) were equally willing to receive a ZIKV vaccine. Hispanic ethnicity, disc...
The American journal of tropical medicine and hygiene, Jan 7, 2018
Limited data exist about U.S. travelers' knowledge, risk perceptions, and behaviors related t... more Limited data exist about U.S. travelers' knowledge, risk perceptions, and behaviors related to the Zika virus (ZIKV). Using an internet research panel, in March 2017, we surveyed 1,202 Americans in the continental United States and Puerto Rico who planned to travel to a Zika-affected country, state, or U.S. territory in 2017. We compared levels of knowledge and perceived risk of ZIKV, and intentions to practice ZIKV prevention behaviors across respondents from three regions: Puerto Rico, at-risk states, and other states. More than 80% of respondents correctly understood that a person could acquire ZIKV through a bite from an infected mosquito, and over 64% of respondents knew that a pregnant woman could pass the virus to her fetus. Less than half of the respondents from at-risk states and other states knew that ZIKV could be transmitted sexually, as compared with three-quarters of respondents from Puerto Rico. Compared with respondents from at-risk and other states, respondents ...
The American journal of tropical medicine and hygiene, Jan 2, 2017
Infestation with Sarcoptes scabiei var. hominis is a common human parasitic affliction endemic in... more Infestation with Sarcoptes scabiei var. hominis is a common human parasitic affliction endemic in tropical developing countries. Scabies is transmitted by close person-person contact, and outbreaks have been reported in reception centers for asylum seekers. Scabies presents clinically as extremely pruritic excoriated papules and linear burrows in the skin. This infestation predisposes to bacterial skin infections that can result in serious complications affecting the kidneys and possibly the heart. Treatment of individuals with scabies and their close contacts involves the use of antiparasitic agents. First-line treatment is topical 5% permethrin cream. Community mass drug administration, followed by active case finding with targeted treatment, is a promising approach that can reduce the prevalence of both scabies and bacterial skin infections. Organizations such as the International Alliance for the Control of Scabies are advocating for the development of integrated disease control...
The nucleotide sequences of the mglA and mglC genes of Salmonella typhimurium (St) LT2 have been ... more The nucleotide sequences of the mglA and mglC genes of Salmonella typhimurium (St) LT2 have been determined. The deduced amino acid (aa) sequences of MglA and MglC are 506 and 302 aa long with predicted molecular masses of 56,484 and 31,551 Da, respectively. The aa sequences of St MglA and MglC are homologous to the corresponding Mgl proteins of Escherichia coli, Haemophilus influenzae, Treponema pallidum and Mycoplasma genitalium. The order of the St mgl operon is mglBAC.
We have characterized a 5.2-kilobase (kb) putative transport related operon (tro) locus of Trepon... more We have characterized a 5.2-kilobase (kb) putative transport related operon (tro) locus of Treponema pallidum subsp. pallidum (Nichols strain) (Tp) encoding six proteins: TroA, TroB, TroC, TroD, TroR and Phosphoglycerate mutase (Pgm). Four of these gene products (TroA-TroD) are homologous to members of the ATP-Binding Cassette (ABC) superfamily of bacterial transport proteins. TroA (previously identified as Tromp1) has significant sequence similarity to a family of Gram-negative periplasmic substrate-binding proteins and to a family of streptococcal proteins that may have dual roles as substrate binding proteins and adhesins. TroB is homologous to the ATP-binding protein component, whereas TroC and TroD are related to the hydrophobic membrane protein components of ABC transport systems. TroR is similar to Gram-positive iron-activated repressor proteins (DesR, DtxR, IdeR, and SirR). The last open reading frame (ORF) of the tro operon encodes a protein that is highly homologous to the glycolytic pathway enzyme, Pgm. Primer extension results demonstrated that the tro operon is transcribed from a sigma 70-type promoter element. Northern analysis and reverse transcriptase-polymerase chain reactions provided evidence for the presence of a primary 1-kb troA transcript and a secondary, less abundant, troA-pgm transcript. The tro operon is flanked by a Holliday structure DNA helicase homolog (upstream) and two ORFs representing a purine nucleoside phosphorylase homolog and tpp15, a previously characterized gene encoding a membrane lipoprotein (downstream). The presence of a complex operon containing a putative ABC transport system and a DtxR homolog indicates a possible linkage between transport and gene regulation in Tp.
The American journal of tropical medicine and hygiene, Jan 2, 2015
Ebola virus disease (EVD) is a life-threatening zoonosis caused by infection with the Ebola virus... more Ebola virus disease (EVD) is a life-threatening zoonosis caused by infection with the Ebola virus. Since the first reported EVD outbreak in the Democratic Republic of the Congo, several small outbreaks have been reported in central Africa with about 2,400 cases occurring between 1976 and 2013. The 2013-2015 EVD outbreak in west Africa is the first documented outbreak in this region and the largest ever with over 27,000 cases and more than 11,000 deaths. Although EVD transmission rates have recently decreased in west Africa, this crisis continues to threaten global health and security, particularly since infected travelers could spread EVD to other resource-limited areas of the world. Because vaccines and drugs are not yet licensed for EVD, outbreak control is dependent on the use of non-pharmaceutical interventions (e.g., infection control practices, isolation of EVD cases, contact tracing with follow-up and quarantine, sanitary burial, health education). However, delays in diagnosi...
The American journal of tropical medicine and hygiene, Jan 13, 2015
Yaws is a neglected infectious disease that affects mostly children and adolescents living in poo... more Yaws is a neglected infectious disease that affects mostly children and adolescents living in poor, rural communities in humid, tropical areas of Africa, southeast Asia, and the Pacific Islands. The etiological agent of yaws, Treponema pallidum subspecies pertenue (T. pertenue), was discovered by Aldo Castellani in 1905 shortly after Schaudinn and Hoffmann discovered the etiological agent of syphilis, T. pallidum subspecies pallidum. The discovery of T. pertenue enabled the development of animal models and the identification of an effective antibiotic treatment (i.e., penicillin) for yaws. A World Health Organization (WHO) mass treatment campaign from 1952 to 1964 reduced the global burden of yaws by 95%, but failed to eradicate this disease. Today, 110 years after Castellani's discovery of T. pertenue, yaws is again targeted for eradication. Recent advances in the treatment and diagnosis of yaws improved the likelihood of success this time. However, several challenges must be o...
The etiology of bovine ulcerative mammary dermatitis (UMD) is poorly characterized. The goal of t... more The etiology of bovine ulcerative mammary dermatitis (UMD) is poorly characterized. The goal of this study was to genetically analyze spirochetes present in UMD lesions. DNA prepared from UMD lesion biopsies and from spirochetes cultured from the corresponding lesion biopsies was PCR amplified using primers for the 16S rDNA-tRNA(ile) intergenic spacer region (ISR) of Treponema 16S-23S rDNA. Analysis of cloned ISR amplicons from three cultivable UMD-associated spirochetes indicated that two isolates cluster closely with cultivable papillomatous digital dermatitis (PDD)-associated and human-associated Treponema phylotypes, while the remaining isolate is unique. Analysis of ISR amplicons from UMD lesion biopsies identified additional not-yet-cultivable Treponema phylotypes. Our results revealed the presence of a genetically diverse Treponema population in an UMD lesion.
The nucleotide sequence of the Treponema pallidum mcp2 gene was determined. mcp2 encodes a 45.8-k... more The nucleotide sequence of the Treponema pallidum mcp2 gene was determined. mcp2 encodes a 45.8-kDa protein whose deduced amino acid sequence has significant homology with the C-terminal region of bacterial methyl-accepting chemotaxis proteins (MCPs). The Mcp2 N terminus lacks the hydrophobic transmembrane regions present in most MCPs. An Mcp2 fusion protein was strongly reactive with antibody (HC23) to the highly conserved domain of MCPs and with rabbit syphilitic serum. Antibody HC23 reacted with six T. pallidum proteins, including a 45-kDa protein that may correspond to Mcp2. This protein was present in the aqueous phase from T. pallidum cells that were solubilized with Triton X-114 and phase partitioned.
A new medium that permits radiolabeling of freshly extracted cells of Treponema pallidum with [35... more A new medium that permits radiolabeling of freshly extracted cells of Treponema pallidum with [35S]methionine very efficiently has been devised. Although treponemes were not purified free of contaminating rabbit tissue, label was incorporated exclusively into treponemal protein in a linear manner for at least the first 16 h of in vitro incubation. Throughout this period, virtually a full complement of treponemal proteins was synthesized, based on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis comparison of the radiolabeled protein profile with the Coomassie blue-stained profile of gradient-purified treponemes. The radiolabeled protein profiles obtained with three pathogenic strains were very similar but not identical. Using solubilized treponemal extracts and a sensitive radioimmunoprecipitation procedure, we identified the protein antigens of T. pallidum that were recognized by immunoglobulin G antibodies in various rabbit and human syphilitic sera. A simple fractionat...
The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and... more The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10, and 1% survival were determined for representative serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay, L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent m...
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