Effect of expanding farmlands with domestication of animals in the vicinity of disturbed swamps and built-up farmland ponds on population dispersion and decline of locally adapted Mansonia vectors (Diptera: Culicidae).

Background and Objectives: The adaptive processes and resilience of Mansonia vectors responsible for bioindicators can change in response to climate, land use, and environmental changes. This study evaluated the effects of expanding farmlands with the domestication of animals in the vicinity of either disturbed swamps or built-up farmland ponds on the population dispersion and decline of locally adapted Mansonia faunas as a result of expanding farmlands in Thailand. Materials and Methods: Based on environmental surveys, four different geographically defined study sites were selected: I - the expanding farmlands with domestication of livestock and pet animals in the vicinity of low-lying swamp with habitat fragmentation and aquatic vegetation; II - the expanding farmlands with domestication of pet animals in the vicinity of elevated swamp with habitat destruction and aquatic vegetation; III - the expanding farmlands with domestication of livestock and pet animals in the vicinity of low-lying farmland ponds with restoration and aquatic vegetation; and IV - the expanding farmlands with domestication of pet animals in the vicinity of elevated farmland ponds with restoration and aquatic vegetation. Human landing catch collection method was used to periodically assess the species composition and abundance of Mansonia vectors. Results: Aggregated distributions and seasonal abundances of Mansonia faunas (Mansonia uniformis, Mansonia indiana, Mansonia annulifera, Mansonia annulata, Mansonia bonneae, and Mansonia dives) with variable proportions were observed at all the study sites. A decline in the population of Mansonia faunas, except for Ma. uniformis, was observed at study sites I and II. Conclusion: The anticipated effects of expanding farmlands affected the population dispersion and decline of locally adapted Mansonia faunas, thus representing a diverse assemblage of Mansonia species with different adaptations, ecological tolerances, and host exploitation strategies in life. These effects depended either on the function of disturbed swamps or on the development of farmland ponds, whether they provided a wide range of freshwater habitats, or on the domestication of animals, whether they provided animal blood meal sources.

Evaluating Antibiotic Treatment Guideline Adherence to Ongoing Antibiotic Stewardship in a Tertiary Care Setting: A Retrospective Observational Study.

Antimicrobial resistance (AMR) is widely regarded as an increasing threat to global public health. Antibiotic treatment guidelines have been increasingly recognized as an effective tool to guide appropriate prescriptions and help curtail antibiotic resistance. The present study aimed to assess physician's adherence to hospital antibiotic treatment guideline recommendations in Nepal and determine predictive variables with a significant association. This was a retrospective, monocentric observational review to investigate the adherence to endorsed guidelines using the medical records of adults admitted to the hospital with a diagnosis of urinary tract infection (UTI), pneumonia, or skin and soft tissue infection (SSTI) from January 2018 to December 2019. Of the 2,077 medical records that were reviewed (954 UTI, 754 pneumonia, and 369 SSTI), 354 (17%) met the study inclusion criteria, which included 87 UTI, 180 pneumonia, and 87 SSTI patients. Among eligible patients with antibiotic prescriptions, the following were adherent to guideline recommendations: 33 (37.9%) UTI, 78 (43.3%) pneumonia, and 23 (26.4%) SSTI. The overall extent of adherence to hospital antibiotic treatment guidelines for the use of antibiotics among adult inpatients diagnosed with these common infections was 37.9%. Patients who received ceftriaxone (OR = 2.09, 95% CI = 1.18-3.71, p=0.012) and levofloxacin (OR = 4.63, 95% CI = 1.30-16.53, p=0.018) had significantly higher adherence to treatment guidelines. This study revealed a low adherence rate despite the availability of updated guidelines for antibiotic prescriptions. The findings confer an urgent need to confront antibiotic prescription patterns in such tertiary care centers for tailored interventions to improve adherence to antibiotic guidelines.

Emergence of zoonotic Brugia pahangi parasite in Thailand.

Zoonotic Brugia pahangi parasite infections in humans have emerged over two decades in Southeast Asia (SEA), including Malaysia and Thailand. The species is commonly found in domestic cats and dogs as the natural reservoir hosts. The sporadic transmission pattern of B. pahangi zoonosis causes childhood infections in Thailand and adulthood infections in Malaysia. It is crucial to understand the vulnerability in how zoonotic B. pahangi parasite is transmitted to susceptible persons in receptive settings and the exposure to the infection under impoverished environment to which the human-vector-animal interactions are related. This acquisition of knowledge will help multiple health science professions to apply One Health approach to strengthening the capacity in diagnosis and surveillance, and hence detecting and monitoring the "lingering" zoonotic B. pahangi infections present in vulnerable populations in Thailand and elsewhere in SEA. In this review article, the authors focused on articulating the concepts of plantation-related zoonotic B. pahangi filariasis by updating current knowledge of B. pahangi life cycle, vector's life cycle and current state of research on the epidemiology and ecology of B. pahangi zoonosis.

Investigation of Armigeres subalbatus, a vector of zoonotic Brugia pahangi filariasis in plantation areas in Suratthani, Southern Thailand.

In recent years, children in Thailand have been infected with zoonotic Brugia pahangi. However, the local environment of rubber or oil palm plantations, which would increase their exposure to risk factors of the infection due to mosquito transmission, is unclear. The present study first sought to determine the extent to which variations in the local landscape, such as the elevated versus low-lying ecotope of rubber or oil palm plantations, in a 2-km radius of the geographically defined landscape in a rural area of Suratthani, Southern Thailand could influence the abundance of Armigeres subalbatus and its susceptibility to zoonotic filarial parasite infections compared to Mansonia, Aedes, and Culex, and Coquillettidia. Thereafter, the filarial larvae found in the infected mosquitoes were molecularly investigated. Ar. subalbatus plantation ecotype was not only found to outnumber the local mosquitoes, but was identified as the predominant species that adapted well to the elevated ecotopes of the rubber or oil palm plantations, which existed at altitudes of 60-80 m. The overall rate of zoonotic filarial parasite infections (L1, L2, or L3 larvae) of Ar. subalbatus was 2.5% (95% CI, -0.2 to 4.1), with an average L3 load of 2.3 larvae per infected Ar. subalbatus (95% CI, -0.6 to 13.0); this is because the infections were found to be concentrated in the elevated ecotopes alone. Based on filarial orthologous ß-tubulin gene-specific touchup-nested PCR and sequence analysis using 30 L3 larva clones as representatives of 9 Ar. subalbatus infectious pools, Ar. subalbatus either carried B. pahangi or Dirofilaria immitis, or both species. Such findings suggest that Ar. subalbatus might have played an imperative role in the transmission of B. pahangi in the plantation areas infested with Ar. subalbatus.

Adaptation of Anopheles Vectors to Anthropogenic Malaria-Associated Rubber Plantations and Indoor Residual Spraying: Establishing Population Dynamics and Insecticide Susceptibility.

Anthropogenic activity such as the establishment of Anopheles-infested rubber plantations can influence local malaria transmission dynamics to which the population dynamics and insecticide susceptibility of local Anopheles vectors are related. Using human landing catch collections at a house protected by indoor residual spraying (IRS), the periodic assessment of species composition, abundance, and blood-feeding behaviors was done in pre-IRS, during IRS, and post-IRS at 3, 6, and 12 months in a malaria-associated rubber plantation (MRP) ecotope of the Bo Rai district, Trat Province, Thailand, after malaria outbreak occurred. The study MRP ecotope elicited the population ratio (pi ) of Anopheles vectors: An. campestris (0.747), An. dirus (0.168), An. minimus (0.037), An. barbirostris (0.027), and An. pseudowillmori (0.002), and of An. jamesii nonvector (0.019). Among these, two predominant An. campestris and An. dirus night-biters were then used in the susceptibility test against 0.05% deltamethrin (DEL) and 0.09% bifenthrin (BT) insecticides currently used in IRS. An. campestris, a suspected vector of Plasmodium vivax, had a tendency to appear throughout the study and behaved both exophagy and endophagy. It was highly susceptible to BT, showing 95.0% mortality (95% CI, 79.1-100) while decreasing sensitivity of 87.2% (95% CI, 78.4-95.9) to DEL. An. dirus, a primary vector of Plasmodium falciparum, had a tendency to feed outdoors rather than indoors. Significant differences in the abundance (mean density and human landing rate) were observed at pre-IRS (P < 0.001 and P=0.046), and similarly, during IRS (P=0.001 and P=0.037). It was highly susceptible to DEL and BT, showing 100% mortality rate. Evidently, the study MRP ecotope contributed receptive environment to favor the abundant local Anopheles vectors and their outdoor biting preference. This can pose the risk for residual malaria parasite transmission in Anopheles vectors even though the house is protected by IRS.

Seasonal and Geographical Variation of Dengue Vectors in Narathiwat, South Thailand.

Using GIS-based land use map for the urban-rural division (the relative ratio of population density adjusted to relatively Aedes-infested land area), we demonstrated significant independent observations of seasonal and geographical variation of Aedes aegypti and Aedes albopictus vectors between Muang Narathiwat district (urban setting) and neighbor districts (rural setting) of Narathiwat, Southern Thailand, based on binomial distribution of Aedes vectors in water-holding containers (water storage containers, discarded receptacles, miscellaneous containers, and natural containers). The distribution of Aedes vectors was influenced seasonally by breeding outdoors rather than indoors in all 4 containers. Accordingly, both urban and rural settings elicited significantly seasonal (wet versus dry) distributions of Ae. aegypti larvae observed in water storage containers (P = 0.001 and P = 0.002) and natural containers (P = 0.016 and P = 0.015), whereas, in rural setting, the significant difference was observed in discarded receptacles (P = 0.028) and miscellaneous containers (P < 0.001). Seasonal distribution of Ae. albopictus larvae in any containers in urban setting was not remarkably noticed, whereas, in rural setting, the significant difference was observed in water storage containers (P = 0.007) and discarded receptacles (P < 0.001). Moreover, the distributions of percentages of container index for Aedes-infested households in dry season were significantly lower than that in other wet seasons, P = 0.034 for urban setting and P = 0.001 for rural setting. Findings suggest that seasonal and geographical variation of Aedes vectors affect the infestation in those containers in human inhabitations and surroundings.

Landscape ecology and epidemiology of malaria associated with rubber plantations in Thailand: integrated approaches to malaria ecotoping.

The agricultural land use changes that are human-induced changes in agroforestry ecosystems and in physical environmental conditions contribute substantially to the potential risks for malaria transmission in receptive areas. Due to the pattern and extent of land use change, the risks or negatively ecosystemic outcomes are the results of the dynamics of malaria transmission, the susceptibility of human populations, and the geographical distribution of malaria vectors. This review focused basically on what are the potential effects of agricultural land use change as a result of the expansion of rubber plantations in Thailand and how significant the ecotopes of malaria-associated rubber plantations (MRP) are. More profoundly, this review synthesized the novel concepts and perspectives on applied landscape ecology and epidemiology of malaria, as well as approaches to determine the degree to which an MRP ecotope as fundamental landscape scale can establish malaria infection pocket(s). Malaria ecotoping encompasses the integrated approaches and tools applied to or used in modeling malaria transmission. The scalability of MRP ecotope depends upon its unique landscape structure as it is geographically associated with the infestation or reinfestation of Anopheles vectors, along with the attributes that are epidemiologically linked with the infections. The MRP ecotope can be depicted as the hotspot such that malaria transmission is modeled upon the MRP factors underlying human settlements and movement activities, health behaviors, land use/land cover change, malaria vector population dynamics, and agrienvironmental and climatic conditions. The systemic and uniform approaches to malaria ecotoping underpin the stratification of the potential risks for malaria transmission by making use of remotely sensed satellite imagery or landscape aerial photography using unmanned aerial vehicle (UAV), global positioning systems (GPS), and geographical information systems (GIS).

Ecotope-based entomological surveillance and molecular xenomonitoring of multidrug resistant malaria parasites in anopheles vectors.

The emergence and spread of multidrug resistant (MDR) malaria caused by Plasmodium falciparum or Plasmodium vivax have become increasingly important in the Greater Mekong Subregion (GMS). MDR malaria is the heritable and hypermutable property of human malarial parasite populations that can decrease in vitro and in vivo susceptibility to proven antimalarial drugs as they exhibit dose-dependent drug resistance and delayed parasite clearance time in treated patients. MDR malaria risk situations reflect consequences of the national policy and strategy as this influences the ongoing national-level or subnational-level implementation of malaria control strategies in endemic GMS countries. Based on our experience along with current literature review, the design of ecotope-based entomological surveillance (EES) and molecular xenomonitoring of MDR falciparum and vivax malaria parasites in Anopheles vectors is proposed to monitor infection pockets in transmission control areas of forest and forest fringe-related malaria, so as to bridge malaria landscape ecology (ecotope and ecotone) and epidemiology. Malaria ecotope and ecotone are confined to a malaria transmission area geographically associated with the infestation of Anopheles vectors and particular environments to which human activities are related. This enables the EES to encompass mosquito collection and identification, salivary gland DNA extraction, Plasmodium- and species-specific identification, molecular marker-based PCR detection methods for putative drug resistance genes, and data management. The EES establishes strong evidence of Anopheles vectors carrying MDR P. vivax in infection pockets epidemiologically linked with other data obtained during which a course of follow-up treatment of the notified P. vivax patients receiving the first-line treatment was conducted. For regional and global perspectives, the EES would augment the epidemiological surveillance and monitoring of MDR falciparum and vivax malaria parasites in hotspots or suspected areas established in most endemic GMS countries implementing the National Malaria Control Programs, in addition to what is guided by the World Health Organization.

Thailand momentum on policy and practice in local legislation on dengue vector control.

Over a past decade, an administrative decentralization model, adopted for local administration development in Thailand, is replacing the prior centralized (top-down) command system. The change offers challenges to local governmental agencies and other public health agencies at all the ministerial, regional, and provincial levels. A public health regulatory and legislative framework for dengue vector control by local governmental agencies is a national topic of interest because dengue control program has been integrated into healthcare services at the provincial level and also has been given priority in health plans of local governmental agencies. The enabling environments of local administrations are unique, so this critical review focuses on the authority of local governmental agencies responsible for disease prevention and control and on the functioning of local legislation with respect to dengue vector control and practices.

O Serogroup-Specific Touchdown-Multiplex Polymerase Chain Reaction for Detection and Identification of Vibrio cholerae O1, O139, and Non-O1/Non-O139.

A novel, sensitive locus-specific touchdown-multiplex polymerase chain reaction (TMPCR), which is based on two-stage amplification pertaining to multiplex PCR and conditional touchdown strategy, was used in detecting and differentiating Vibrio cholerae serogroups. A panel of molecular marker-based TMPCR method generates reproducible profiles of V. cholerae-specific (588 bp) amplicons derived from ompW gene encoding the outer membrane protein and serogroup-specific amplicons, 364 bp for the O1 and 256 bp for the O139, authentically copied from rfb genes responsible for the lipopolysaccharide biosynthesis. The TMPCR amplification efficiency yields either equally or unequally detectable duplex DNA bands of the O1 (588 and 364 bp) and O139 (588 and 256 bp) or a DNA fragment of non-O1/non-O139 (588 bp) while providing no false positive identifications using the genomic DNA templates of the other vibrios and Enterobacteriaceae. The reciprocal analysis of two-template combinations demonstrated that, using V. cholerae O1, O139, or equally mixed O1 and O139, the TMPCR had a detection limit of as low as 100 pg of the O1, O139, or non-O1/non-O139 in reactions containing unequally or equally mixed gDNAs. In addition, the O serogroup-specific TMPCR method had 100% agreement with the serotyping method when examined for the serotyped V. cholerae reference strains and those recovered from clinical samples. The potential benefit of using this TMPCR tool would augment the serotyping method used in epidemiological surveillance and monitoring of V. cholerae serogroups, O1, O139, and non-O1/non-O139 present in clinical and environmental samples.

Border malaria associated with multidrug resistance on Thailand-Myanmar and Thailand-Cambodia borders: transmission dynamic, vulnerability, and surveillance.

This systematic review elaborates the concepts and impacts of border malaria, particularly on the emergence and spread of Plasmodium falciparum and Plasmodium vivax multidrug resistance (MDR) malaria on Thailand-Myanmar and Thailand-Cambodia borders. Border malaria encompasses any complex epidemiological settings of forest-related and forest fringe-related malaria, both regularly occurring in certain transmission areas and manifesting a trend of increased incidence in transmission prone areas along these borders, as the result of interconnections of human settlements and movement activities, cross-border population migrations, ecological changes, vector population dynamics, and multidrug resistance. For regional and global perspectives, this review analyzes and synthesizes the rationales pertaining to transmission dynamics and the vulnerabilities of border malaria that constrain surveillance and control of the world's most MDR falciparum and vivax malaria on these chaotic borders.

Malaria-associated rubber plantations in Thailand.

Rubber forestry is intentionally used as a land management strategy. The propagation of rubber plantations in tropic and subtropic regions appears to influence the economical, sociological and ecological aspects of sustainable development as well as human well-being and health. Thailand and other Southeast Asian countries are the world's largest producers of natural rubber products; interestingly, agricultural workers on rubber plantations are at risk for malaria and other vector-borne diseases. The idea of malaria-associated rubber plantations (MRPs) encompasses the complex epidemiological settings that result from interactions among human movements and activities, land cover/land use changes, agri-environmental and climatic conditions and vector population dynamics. This paper discusses apparent issues pertaining to the connections between rubber plantations and the populations at high risk for malaria. The following questions are addressed: (i) What are the current and future consequences of rubber plantations in Thailand and Southeast Asia relative to malaria epidemics or outbreaks of other vector-borne diseases? (ii) To what extent is malaria transmission in Thailand related to the forest versus rubber plantations? and (iii) What are the vulnerabilities of rubber agricultural workers to malaria, and how contagious is malaria in these areas?

Predictors of malaria-association with rubber plantations in Thailand.

BACKGROUND: The national Global Fund-supported malaria (GFM) program in Thailand, which focuses on the household-level implementation of vector control via insecticide-treated nets (ITNs)/long-lasting insecticidal nets (LLINs) combined with indoor residual spraying (IRS), has been combating malaria risk situations in different provinces with complex epidemiological settings. By using the perception of malaria villagers (MVs), defined as villagers who recognized malaria burden and had local understanding of mosquitoes, malaria, and ITNs/LLINs and practiced preventive measures, this study investigated the predictors for malaria that are associated with rubber plantations in an area of high household-level implementation coverage of IRS (2007-2010) and ITNs/LLINs (2008-2010) in Prachuap Khiri Khan Province. METHODS: A structured questionnaire addressing socio-demographics, household characteristics and health behavioral factors (knowledge, perceptions and practices) regarding the performed interventions was administered to the 313 households (70 malaria-affected and 243 malaria-unaffected) that had respondents aged ≥18 years of both genders. In the univariate and multivariate analyses, only 246 (78.6%) MV respondents (62 malaria-affected and 184 malaria-unaffected) were analyzed to determine the predictors for risk (morbidity). RESULTS: The majority (70%) of households were covered by IRS. For a combination of ITNs/LLINs, there were 74% of malaria-affected households covered and 46% of malaria-unaffected households. In a logistic regression analysis using odds ratios (aORs) adjusted on the variables and a 95% confidence interval (CI), malaria affecting MVs was associated with daily worker (i.e., earning daily income by normally practicing laborious activities mostly in agriculture such as rubber tapping and rubber sheet processing at the smallholdings of rubber plantations) (aOR = 2.9, 95% CI: 1.1-7.4), low-moderate level of malaria knowledge (aOR = 2.4, 95% CI: 1.1-5.0) and sleeping under mosquito-nets (nets/ITNs/LLINs intermittently and ITNs/LLINs only) (aOR = 2.0, 95% CI: 1.0-3.7). CONCLUSIONS: The MV predictors for malaria-association with rubber plantations included occupation (daily worker), misconceptions about malaria (mosquito and prevention) and the use of mosquito-nets. Human practices such as revisiting rubber plantations while exposed to multiple bites at multiple locations are more likely to apply to daily workers than to rubber farmers/tappers and others. The promotion and use of ITNs/LLINs depends substantially on cultural factors and defensive behaviors relevant to their occupational risk despite the perceived threats of malaria and the perceived benefits of ITNs/LLINs. This information supports the conclusion that GFM program implementation in Thailand or elsewhere for malaria-associated with rubber plantations would benefit from the potential use of ITNs/LLINs and changes in personal protection behaviors.

Risk factors for malaria infection among rubber tappers living in a malaria control program area in southern Thailand.

Rubber tappers work begins at midnight during the feeding time of Anopheles maculatus and An. minimus, two common malaria vectors in southern Thailand. We studied the association between rubber tapper behavior and malaria infections as reported to the Notified Disease Surveillance System during 2010 in Prachuab Khiri Khan Province, Thailand. In that province insecticide treated bednets are distributed free to the population and insecticide residual spraying is performed annually. A random sample of 394 rubber tapper households was interviewed from October 2010 to May 2011. Twenty-six households (6.6%) had at least one family member who contracted malaria during 2010. Poisson regression was used to identify potential characteristics associated with malaria. Multilevel Poisson regression was used to test for simultaneous effects of tapper behavior and household risk for malaria infection. The estimated incidence rate ratio (IRR) for contracting malaria among those owning a farming hut was 2.9 (95% CI 1.1-7.3, p < 0.05) after controlling for other variables. Even in areas where control programs are in place, malaria infection among rubber tappers is common. Given the Thai Government's plan to expand the rubber plantation areas to other regions of the country without specific prevention for this at-risk population, the malaria burden in Thailand may increase.

Touchdown-touchup nested PCR for low-copy gene detection of benzimidazole-susceptible Wuchereria bancrofti with a Wolbachia endosymbiont imported by migrant carriers.

A novel, sensitive and specific touchdown-touchup nested PCR (TNPCR) technique based on two useful molecular markers, a Wuchereria bancrofti ß-tubulin gene involved in benzimidazole susceptibility and a Wolbachia ftsZ gene involved in cell division, was developed to simultaneously detect the parasite W. bancrofti (W1) with its Wolbachia endosymbiont (W2) from both microfilaremic and post-treatment samples of at-risk migrant carriers infected with geographical W. bancrofti isolates. The detection and characterization of authentically low-copy gene-derived amplicons revealed no false positive identifications in amicrofilaremia with or without antigenemia. The W1-TNPCR was 100-fold more sensitive than the W2-TNPCR regardless of the microfilarial DNA isolation method and compared well with the thick blood film and membrane filtration techniques. These locus-specific TNPCRs could also detect Wolbachia-carrying W. bancrofti genotype in addition to a link to benzimidazole sensitivity among those with unknown infection origins that exhibited microfilaremia responsiveness against treatment with diethylcarbamazine plus albendazole. These TNPCR methods can augment the results of microscopic detection of the parasite because these methods enhance DNA isolation and PCR amplification capabilities.

Identification of Entamoeba histolytica and Entamoeba dispar by PCR assay of fecal specimens obtained from Thai/Myanmar border region.

Due to the indistinguishable morphology between Entamoeba histolytica (pathogenic) and Entamoeba dispar (non pathogenic), PCR-based assays were conducted. Based on microscopy, suspected Entamoeba cells were detected in 30 out of 455 fecal samples obtained from individuals residing at Thai/Myanmar border region. The target genes for PCR amplification included genes encoding small subunit rRNA (SSU-rRNA), chitinase and serine rich Entamoeba protein. PCR primers derived from SSU-rRNA gene amplified both E. histolytica and E. dispar genes producing an amplicon of 1,080 bp, and detected 3 out of 30 samples. PCR primers derived from chitinase gene of E. histolytica generating amplicons of 500 and 1,260 bp, samples were positive in 12 out of 30 samples. Due the large difference of gene encoding serine rich protein between E. histolytica and E. dispar, two specific sets of primers were designed. SREH-primer set, specific for E. histolytica, generated amplicons of 550 and 700 bp and detected 22 out of 30 samples. SED-primer set, specific to E. dispar, produced an amplicon of 550 bp, and together with a nested primer pair generating an amplicon of 477 bp, detected 16 out of 30 samples. Thus, detection of single and mixed infections of the two Entamoeba species could be effectively achieved directly from DNA extracted from feces without the need to culture the parasites.

Enhancement of Legionella pneumophila culture isolation from microenvironments by macrophage infectivity potentiator (mip) gene-specific nested polymerase chain reaction.

The combination of a Legionella pneumophila culture isolation technique and macrophage infectivity potentiator (mip) gene-specific nested polymerase chain reaction (PCR) is pivotal for effective routine use in an environmental water system laboratory. Detection of Legionella organisms in 169 environmental samples was performed by using modified buffered charcoal yeast extract (MBCYE) agar for conventional culture. Nested PCR specific for L. pneumophila was performed using boiled genomic DNA extracts from filtered and Chelex 100-treated water samples, or by using silica-gel membrane spin column-eluted DNA from concentrated pond, canal and river samples. Overall, the nested PCR was twelvefold more sensitive than the culture method. The target amplicons (471 basepairs) of all 4 biochemically characterized L. pneumophila isolates were sequenced. They had homology at the DNA and protein levels to 3' proximity of the mip-coding gene of L. pneumophila deposited in genome databases. EcoRI- or KpnI-digested PCR fragments with expected sizes were also confirmed in all 52 PCR-positive samples that were isolated from cooling towers and condenser drains. Viable but nonculturable L. pneumophila might have been present in 48 PCR-positive samples. This study demonstrates that detection of the genetically stable mip gene by nested PCR with a modified process of water sample preparation can be rapidly and effectively used to enhance isolation of the L. pneumophila taxon from microenvironments.

Adverse reactions of 300 MG diethylcarbamazine, and in a combination of 400 MG albendazole, for a mass annual single dose treatment, in migrant workers in Phang Nga province.

BACKGROUND: Foreign migrant workers with work permits in Thailand are given once a year 300 mg diethyl-carbamazine (DEC) for bancroftian filariasis, and 400 mg albendazole (ABZ) for helminthiasis. Treatment effectiveness, tolerability, and safety of two treatment arms, DEC + ABZ and DEC alone, had never been fully documented. OBJECTIVE: Evaluate the tolerability of the two treatment arms and analyze the effects of adverse reaction, prevalence, and intensity of both common and uncommon adverse drug reactions (ADR) in relation to the reaction time (2 hours = acute, > 2 to 24 hours = subacute, and > 24 to 72 hours = latent). MATERIAL AND METHOD: A hospital-based clinical study of on-hour-2 treatment with both treatment arms in 280 Myanmar male migrant volunteers (DEC + ABZ = 150, DEC = 130) was conducted in Phang Nga province, southern Thailand Of these, ADR evaluation at three reaction times was performed using antigenemic (WbAg+) and non-antigenemic (WbAg-) volunteer groups (DEC + ABZ/WbAg+ = 14, DEC/WbAg+ = 12, DEC + ABZ/ WbAg- = 8, andDEC/WbAg- = 16). RESULTS: Both drug groups had similarly overall ADR prevalence [5.2%for DEC + ABZ and 5. 1% for DEC (p > 0. 05)], as well as mean ADRacute scores (p > 0. 05) on hour 2 post-treatment. The four groups had maximum overall prevalence (10% to 40%for ADRsubacute). It was more likely to show no relationship between treatment arms and WbAg (neither WbAg+ nor WbAg-) with adverse reaction intensity for ADRacute, ADRsubacute, Or ADRlatent Three major specific ADR were fatigue, dizziness, and headache. CONCLUSION: Adverse reaction prevalence and intensity were independent for WbAg and treatment arm. The DEC + ABZ have no greater effects on ADR development as the DEC does. The common ADR after treatment are not required for symptomatic treatment. The study confirms DEC + ABZ regime can be safe and not toxic for use in mass treatment of those migrants in Thailand and, its value, in a mass annual single dose treatment, is beneficial for the Global Alliance to Eliminate of Lymphatic Filariasis (GAELF).

Efficacy of a single-dose treatment with 300 mg diethylcarbamazine and a combination of 400 mg albendazole in reduction of Wuchereria bancrofti antigenemia and concomitant geohelminths in Myanmar migrants in Southern Thailand.

BACKGROUND: There seems to be a large magnitude of parasitic worm loads caused by nocturnally periodic Wuchereria bancrofti and geohelminths, in cross-border Myanmar migrant workers in Thailand. We are therefore considering an effective Mass Drug Administration (MDA) with Diethylcarbamazine (DEC) and Albendazole (ABZ). Due to short periods of their residency and current situation of W. bancrofti antigenemics and concomitant geohelminths, treatment effects on the containment of the infections need to be analyzed. OBJECTIVES: Analyze short-term effects on reduction of W. bancrofti antigen (WbAg) and geohelminths' egg (GhE) loads. The efficacy of a single-dose combined treatment with 300 mg DEC (for filariasis) and 400 mg ABZ (for helminthiasis) was evaluated and compared with a single-dose treatment arm with 300 mg DEC alone. MATERIAL AND METHOD: A randomized clinical trial of two treatment choices in 28 Myanmar male workers (DEC/ABZ or group I = 15, DEC or group II = 13) was conducted in Phang Nga province, Southern Thailand. Because of the withdrawal of three subjects of the DEC group, all the 10 DEC subjects were follow-up monitored at post treatment 2, 4, 8 and 12 weeks. Their mean age was 26.4 years; worm loads (mean +/- SD x 10(3)) of W. bancrofti, Ascaris and Trichuris was 103.9 +/- 44.1 antigen units (AU)/ml, 47.3 +/- 38.7 eggs per gram (EPG) and 16.6 +/- 22.2 EPG respectively. The data on the 15 DEC/ABZ subjects showed a mean age of 25.7 years; corresponding worm loads = 96.1 +/- 54.6 AU/ml, 397.0 +/- 117.3 EPG and 54.5 +/- 42.8 EPG respectively. The Antigen Reduction Rates (ARR) and Egg Reduction Rates (ERR) were presented. RESULTS: At the 12-week post treatment, WbAg loads (mean +/- SD x 10(3) AU/ml) were 61.5 +/- 58.4 for group I and 76.8 +/- 40.7 for group II. A significant WbAg reduction was noted for both groups at weeks 8 and 12 (p < 0.05). Also, the significant reduction of GhE loads was more pronounced for both groups after week 2 (p < 0.05). When comparing efficacy of the treatment choices by the treatment retention time, it was more likely to show both groups had similar adulticidal effects on either WbAg, denoted as the ARR (F = 0. 064, p = 0.806) or GhE, denoted as the ERR (F = 0.196, p = 0.669). CONCLUSION: The single-dose 300 mg DEC plus 400 mg ABZ, or 300 mg DEC alone, can be effectively used for treating infections with W. bancrofti and concomitant geohelminths commonly observed in the area. But treatment rounds are required to clear the infections. The reduction of the parasitic worm loads in the legal Myanmar migrants provide values in monitoring and evaluating an effective MDA program with the DEC/ABZ at the provincial level.

Surveillance of imported bancroftian filariasis after two-year multiple-dose diethylcarbamazine treatment.

Myanmar migrants are at increased risk for nocturnally periodic Wuchereria bancrofti causing imported bancroftian filariasis. They have a significant influence on the effectiveness of diethylcarbamazine (DEC) mass treatment at the provincial level in the National Program to Eliminate Lymphatic Filariasis (PELF) during the fiscal years (FY) 2002-2006, in Thailand. Two oral doses of DEC 6 mg/kg are given twice a year to the eligible Myanmar migrants (> or = 2 years old). A 300 mg DEC provocation test is given once a year to all Myanmar migrants with work permits. Effectiveness evaluation parameters, such as cumulative index (CI) and the effectiveness ratio (ER), were obtained after 2 years of the multiple-dose DEC treatment program in Ranong Province, Southern Thailand. By cross-sectional night blood surveys at the end of FY 2003 in two districts of Ranong Province, the microfilarial positive rates (MPR) were 0.8% and 1.2% for Mueang Ranong and Kra Buri, respectively. The MPR in the agricultural (1.5%) and industrial (0.4%) occupations were not significantly different from each other. Our findings suggest that most untreated microfilaremics working in agriculture, with short-term residency in Thailand, may have delayed multiple-dose DEC treatment.