Differences in Pertussis Incidence by Race and Ethnicity in the United States, 2010-2017

Background

An increased pertussis burden has been demonstrated among Hispanic or Latino and American Indian or Alaska Native (AI/AN) infants. However, data on potential disparities among other age and racial groups are limited.

Methods

We analyzed pertussis cases reported through Enhanced Pertussis Surveillance from 2010 to 2017. Pertussis and severe pertussis incidence were calculated by race (White, Black or African American, AI/AN, and Asian or Pacific Islanders), ethnicity (Hispanic or Latino and non-Hispanic or non-Latino), and age.

Results

Compared with White persons, overall incidence was lower among Black or African American (incidence rate ratio [IRR], .57; 95% confidence interval [CI], .53-.61), AI/AN (IRR, 0.65; 95% CI, .58-.72), and Asian or Pacific Islander persons (IRR, 0.39; 95% CI, .35-.43). Overall incidence of pertussis was higher (1.5-fold; 95% CI, 1.37-1.60) among Hispanic or Latino compared with non-Hispanic or non-Latino adults, potentially related to household size or lower pertussis vaccine uptake among adult Hispanic or Latino cases. Severe pertussis incidence was similar among Black or African American and AI/AN persons compared with White persons. Among infants, severe pertussis incidence was 1.4-fold higher (95% CI, 1.03-1.82) among Black or African American infants than among White infants, and 2.1-fold higher (95% CI, 1.67-2.57) among Hispanic or Latino infants than non-Hispanic or non-Latino infants.

Conclusions

The contrast between lower reported incidence but similar or higher severe pertussis incidence among Black or African American and AI/AN persons compared with White persons warrants further investigation and may reflect underdiagnosis or underreporting of mild disease.

Poliovirus type 1 systemic humoral and intestinal mucosal immunity induced by monovalent oral poliovirus vaccine, fractional inactivated poliovirus vaccine, and bivalent oral poliovirus vaccine: A randomized controlled trial

BACKGROUND

To inform response strategies, we examined type 1 humoral and intestinal immunity induced by 1) one fractional inactivated poliovirus vaccine (fIPV) dose given with monovalent oral poliovirus vaccine (mOPV1), and 2) mOPV1 versus bivalent OPV (bOPV).

METHODS

We conducted a randomized, controlled, open-label trial in Dhaka, Bangladesh. Healthy infants aged 5 weeks were block randomized to one of four arms: mOPV1 at age 6-10-14 weeks/fIPV at 6 weeks (A); mOPV1 at 6-10-14 weeks/fIPV at 10 weeks (B); mOPV1 at 6-10-14 weeks (C); and bOPV at 6-10-14 weeks (D). Immune response at 10 weeks and cumulative response at 14 weeks was assessed among the modified intention-to-treat population, defined as seroconversion from seronegative (<1:8 titers) to seropositive (≥1:8) or a four-fold titer rise among seropositive participants sustained to age 18 weeks. We examined virus shedding after two doses of mOPV1 with and without fIPV, and after the first mOPV1 or bOPV dose. The trial is registered at ClinicalTrials.gov (NCT03722004).

FINDINGS

During 18 December 2018 - 23 November 2019, 1,192 infants were enrolled (arms A:301; B:295; C:298; D:298). Immune responses at 14 weeks did not differ after two mOPV1 doses alone (94% [95% CI: 91-97%]) versus two mOPV1 doses with fIPV at 6 weeks (96% [93-98%]) or 10 weeks (96% [93-98%]). Participants who received mOPV1 and fIPV at 10 weeks had significantly lower shedding (p < 0·001) one- and two-weeks later compared with mOPV1 alone. Response to one mOPV1 dose was significantly higher than one bOPV dose (79% versus 67%; p < 0·001) and shedding two-weeks later was significantly higher after mOPV1 (76% versus 56%; p < 0·001) indicating improved vaccine replication. Ninety-nine adverse events were reported, 29 serious including two deaths; none were attributed to study vaccines.

INTERPRETATION

Given with the second mOPV1 dose, fIPV improved intestinal immunity but not humoral immunity. One mOPV1 dose induced higher humoral and intestinal immunity than bOPV.

FUNDING

U.S. Centers for Disease Control and Prevention.

Status of New Vaccine Introduction - Worldwide, 2016-2021

This report describes the status of introductions globally for eight World Health Organization (WHO)-recommended new and underutilized vaccines, comprising 10 individual vaccine antigens. By 2021, among 194 countries worldwide, 33 (17%) provided all of these 10 WHO-recommended antigens as part of their routine immunization schedules; only one low-income country had introduced all of these recommended vaccines. Universal hepatitis B birth dose; human papillomavirus vaccine; rotavirus vaccine; and diphtheria, tetanus, and pertussis-containing vaccine first booster dose have been introduced by 57%, 59%, 60%, and 72% of all countries worldwide, respectively. Pneumococcal conjugate vaccine, rubella-containing vaccine, measles-containing vaccine second dose, and Haemophilus influenzae type b vaccine have been introduced by 78%, 89%, 94%, and 99% of all countries, respectively. The annual rate of new vaccine introductions declined precipitously when the COVID-19 pandemic started, from 48 in 2019 to 15 in 2020 before rising to 26 in 2021. Increased efforts to accelerate new and underutilized vaccine introductions are urgently needed to improve universal equitable access to all recommended vaccines to achieve the global Immunization Agenda 2021-2030 (IA2030) targets.

CDC's COVID-19 International Vaccine Implementation and Evaluation Program and Lessons from Earlier Vaccine Introductions

The US Centers for Disease Control and Prevention (CDC) supports international partners in introducing vaccines, including those against SARS-CoV-2 virus. CDC contributes to the development of global technical tools, guidance, and policy for COVID-19 vaccination and has established its COVID-19 International Vaccine Implementation and Evaluation (CIVIE) program. CIVIE supports ministries of health and their partner organizations in developing or strengthening their national capacities for the planning, implementation, and evaluation of COVID-19 vaccination programs. CIVIE's 7 priority areas for country-specific technical assistance are vaccine policy development, program planning, vaccine confidence and demand, data management and use, workforce development, vaccine safety, and evaluation. We discuss CDC's work on global COVID-19 vaccine implementation, including priorities, challenges, opportunities, and applicable lessons learned from prior experiences with Ebola, influenza, and meningococcal serogroup A conjugate vaccine introductions.

SARS-CoV-2 Breakthrough Infections among US Embassy Staff Members, Uganda, May-June 2021

The SARS-CoV-2 Delta variant emerged shortly after COVID-19 vaccines became available in 2021. We describe SARS-CoV-2 breakthrough infections in a highly vaccinated, well-monitored US Embassy community in Kampala, Uganda. Defining breakthrough infection rates in highly vaccinated populations can help determine public health messaging, guidance, and policy globally.

Vaccination information, motivations, and barriers in the context of meningococcal serogroup A conjugate vaccine introduction: A qualitative assessment among caregivers in Burkina Faso, 2018

BACKGROUND

In March 2017, Burkina Faso introduced meningococcal serogroup A conjugate vaccine (MACV) into the Expanded Programme on Immunization. MACV is administered to children aged 15-18 months, concomitantly with the second dose of measles-containing vaccine (MCV2). One year after MACV introduction, we assessed the sources and content of immunization information available to caregivers and explored motivations and barriers that influence their decision to seek MACV for their children.

METHODS

Twenty-four focus group discussions (FGDs) were conducted with caregivers of children eligible for MACV and MCV2. Data collection occurred in February-March 2018 in four purposively selected districts, each from a separate geographic region; within each district, caregivers were stratified into groups based on whether their children were unvaccinated or vaccinated with MACV. FGDs were recorded and transcribed. Transcripts were coded and analyzed using qualitative content analysis.

RESULTS

We identified many different sources and content of information about MACV and MCV2 available to caregivers. Healthcare workers were most commonly cited as the main sources of information; caregivers also received information from other caregivers in the community. Caregivers' motivations to seek MACV for their children were driven by personal awareness, engagements with trusted messengers, and perceived protective benefits of MACV against meningitis. Barriers to MACV and MCV2 uptake were linked to the unavailability of vaccines, immunization personnel not providing doses, knowledge gaps about the 15-18 month visit, practical constraints, past negative experiences, sociocultural influences, and misinformation, including misunderstanding about the need for MCV2.

CONCLUSIONS

MACV and MCV2 uptake may be enhanced by addressing vaccination barriers and effectively communicating vaccination information and benefits through trusted messengers such as healthcare workers and other caregivers in the community. Educating healthcare workers to avoid withholding vaccines, likely due to fear of wastage, may help reduce missed opportunities for vaccination.

Meningococcal carriage 7 years after introduction of a serogroup A meningococcal conjugate vaccine in Burkina Faso: results from four cross-sectional carriage surveys

BACKGROUND

In the first 2 years after a nationwide mass vaccination campaign of 1-29-year-olds with a meningococcal serogroup A conjugate vaccine (MenAfriVac) in Burkina Faso, carriage and disease due to serogroup A Neisseria meningitidis were nearly eliminated. We aimed to assess the long-term effect of MenAfriVac vaccination on meningococcal carriage and herd immunity.

METHODS

We did four cross-sectional studies of meningococcal carriage in people aged 9 months to 36 years in two districts of Burkina Faso between May 2, 2016, and Nov 6, 2017. Demographic information and oropharyngeal swabs were collected. Meningococcal isolates were characterised using whole-genome sequencing.

FINDINGS

Of 14 295 eligible people, 13 758 consented and had specimens collected and laboratory results available, 1035 of whom were meningococcal carriers. Accounting for the complex survey design, prevalence of meningococcal carriage was 7·60% (95% CI 5·67-9·52), including 6·98% (4·86-9·11) non-groupable, 0·48% (0·01-0·95) serogroup W, 0·10% (0·01-0·18) serogroup C, 0·03% (0·00-0·80) serogroup E, and 0% serogroup A. Prevalence ranged from 5·44% (95% CI 4·18-6·69) to 9·14% (6·01-12·27) by district, from 4·67% (2·71-6·64) to 11·17% (6·75-15·59) by round, and from 3·39% (0·00-8·30) to 10·43% (8·08-12·79) by age group. By clonal complex, 822 (88%) of 934 non-groupable isolates were CC192, all 83 (100%) serogroup W isolates were CC11, and nine (69%) of 13 serogroup C isolates were CC10217.

INTERPRETATION

Our results show the continued effect of MenAfriVac on serogroup A meningococcal carriage, for at least 7 years, among vaccinated and unvaccinated cohorts. Carriage prevalence of epidemic-prone serogroup C CC10217 and serogroup W CC11 was low. Continued monitoring of N meningitidis carriage will be crucial to further assess the effect of MenAfriVac and inform the vaccination strategy for future multivalent meningococcal vaccines.

FUNDING

Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.

MenAfriNet: A Network Supporting Case-Based Meningitis Surveillance and Vaccine Evaluation in the Meningitis Belt of Africa

Meningococcal meningitis remains a significant public health threat, especially in the African meningitis belt where Neisseria meningitidis serogroup A historically caused large-scale epidemics. With the rollout of a novel meningococcal serogroup A conjugate vaccine (MACV) in the belt, the World Health Organization recommended case-based meningitis surveillance to monitor MACV impact and meningitis epidemiology. In 2014, the MenAfriNet consortium was established to support strategic implementation of case-based meningitis surveillance in 5 key countries: Burkina Faso, Chad, Mali, Niger, and Togo. MenAfriNet aimed to develop a high-quality surveillance network using standardized laboratory and data collection protocols, develop sustainable systems for data management and analysis to monitor MACV impact, and leverage the surveillance platform to perform special studies. We describe the MenAfriNet consortium, its history, strategy, implementation, accomplishments, and challenges.

Health workers' perceptions and challenges in implementing meningococcal serogroup a conjugate vaccine in the routine childhood immunization schedule in Burkina Faso

BACKGROUND

Meningococcal serogroup A conjugate vaccine (MACV) was introduced in 2017 into the routine childhood immunization schedule (at 15-18 months of age) in Burkina Faso to help reduce meningococcal meningitis burden. MACV was scheduled to be co-administered with the second dose of measles-containing vaccine (MCV2), a vaccine already in the national schedule. One year following the introduction of MACV, an assessment was conducted to qualitatively examine health workers' perceptions of MACV introduction, identify barriers to uptake, and explore opportunities to improve coverage.

METHODS

Twelve in-depth interviews were conducted with different cadres of health workers in four purposively selected districts in Burkina Faso. Districts were selected to include urban and rural areas as well as high and low MCV2 coverage areas. Respondents included health workers at the following levels: regional health managers (n = 4), district health managers (n = 4), and frontline healthcare providers (n = 4). All interviews were recorded, transcribed, and thematically analyzed using qualitative content analysis.

RESULTS

Four themes emerged around supply and health systems barriers, demand-related barriers, specific challenges related to MACV and MCV2 co-administration, and motivations and efforts to improve vaccination coverage. Supply and health systems barriers included aging cold chain equipment, staff shortages, overworked and poorly trained staff, insufficient supplies and financial resources, and challenges with implementing community outreach activities. Health workers largely viewed MACV introduction as a source of motivation for caregivers to bring their children for the 15- to 18-month visit. However, they also pointed to demand barriers, including cultural practices that sometimes discourage vaccination, misconceptions about vaccines, and religious beliefs. Challenges in co-administering MACV and MCV2 were mainly related to reluctance among health workers to open multi-dose vials unless enough children were present to avoid wastage.

CONCLUSIONS

To improve effective administration of vaccines in the second-year of life, adequate operational and programmatic planning, training, communication, and monitoring are necessary. Moreover, clear policy communication is needed to help ensure that health workers do not refrain from opening multi-dose vials for small numbers of children.

Evaluation of the Impact of Meningococcal Serogroup A Conjugate Vaccine Introduction on Second-Year-of-Life Vaccination Coverage in Burkina Faso

BACKGROUND

After successful meningococcal serogroup A conjugate vaccine (MACV) campaigns since 2010, Burkina Faso introduced MACV in March 2017 into the routine Expanded Programme for Immunization schedule at age 15-18 months, concomitantly with second-dose measles-containing vaccine (MCV2). We examined MCV2 coverage in pre- and post-MACV introduction cohorts to describe observed changes regionally and nationally.

METHODS

A nationwide household cluster survey of children 18-41 months of age was conducted 1 year after MACV introduction. Coverage was assessed by verification of vaccination cards or recall. Two age groups were included to compare MCV2 coverage pre-MACV introduction (30-41 months) versus post-MACV introduction (18-26 months).

RESULTS

In total, 15 925 households were surveyed; 7796 children were enrolled, including 3684 30-41 months of age and 3091 18-26 months of age. Vaccination documentation was observed for 86% of children. The MACV routine coverage was 58% (95% confidence interval [CI], 56%-61%) with variation by region (41%-76%). The MCV2 coverage was 62% (95% CI, 59%-65%) pre-MACV introduction and 67% (95% CI, 64%-69%) post-MACV introduction, an increase of 4.5% (95% CI, 1.3%-7.7%). Among children who received routine MACV and MCV2, 93% (95% CI, 91%-94%) received both at the same visit. Lack of caregiver awareness about the 15- to 18-month visit and vaccine unavailability were common reported barriers to vaccination.

CONCLUSIONS

A small yet significant increase in national MCV2 coverage was observed 1 year post-MACV introduction. The MACV/MCV2 coadministration was common. Findings will help inform strategies to strengthen second-year-of-life immunization coverage, including to address the communication and vaccine availability barriers identified.

Gametocyte Carriage, Antimalarial Use, and Drug Resistance in Cambodia, 2008-2014

Gametocytes are the malaria parasite stages responsible for transmission from humans to mosquitoes. Gametocytemia often follows drug treatment, especially as therapies start to fail. We examined Plasmodium falciparum gametocyte carriage and drug resistance profiles among 824 persons with uncomplicated malaria in Cambodia to determine whether prevalent drug resistance and antimalarial use has led to a concentration of drug-resistant parasites among gametocyte carriers. Although report of prior antimalarial use increased from 2008 to 2014, the prevalence of study participants presenting with microscopic gametocyte carriage declined. Gametocytemia was more common in those reporting antimalarial use within the past year, and prior antimalarial use was correlated with higher IC₅₀s to piperaquine and mefloquine, as well as to increased pfmdr1 copy number. However, there was no association between microscopic gametocyte carriage and parasite drug resistance. Thus, we found no evidence that the infectious reservoir, marked by those carrying gametocytes, is enriched with drug-resistant parasites.

Matched Placental and Circulating Plasmodium falciparum Parasites are Genetically Homologous at the var2csa ID1-DBL2X Locus by Deep Sequencing

In pregnancy-associated malaria, infected erythrocytes accumulate in the placenta. It is unclear if in polyclonal infections this results in distinct peripheral and placental parasite populations. We used long amplicon deep sequencing of Plasmodium falciparum var2csa ID1-DBL2X from 15 matched peripheral and placental samples collected at delivery from a high transmission area to determine genetic homology. Despite substantial sequence variation and detecting 23 haplotypes, the matched pairs mostly contained the same genetic variants, with 11 pairs sharing 100% of their variants, whereas others showed some heterogeneity. Thus, at delivery, peripheral and placental parasites appear to intermix and placental genotypes can be inferred through peripheral sampling.

Outbreak of Neisseria meningitidis serogroup C outside the meningitis belt-Liberia, 2017: an epidemiological and laboratory investigation

BACKGROUND

On April 25, 2017, a cluster of unexplained illnesses and deaths associated with a funeral was reported in Sinoe County, Liberia. Molecular testing identified Neisseria meningitidis serogroup C (NmC) in specimens from patients. We describe the epidemiological investigation of this cluster and metagenomic characterisation of the outbreak strain.

METHODS

We collected epidemiological data from the field investigation and medical records review. Confirmed, probable, and suspected cases were defined on the basis of molecular testing and signs or symptoms of meningococcal disease. Metagenomic sequences from patient specimens were compared with 141 meningococcal isolate genomes to determine strain lineage.

FINDINGS

28 meningococcal disease cases were identified, with dates of symptom onset from April 21 to April 30, 2017: 13 confirmed, three probable, and 12 suspected. 13 patients died. Six (21%) patients reported fever and 23 (82%) reported gastrointestinal symptoms. The attack rate for confirmed and probable cases among funeral attendees was 10%. Metagenomic sequences from six patient specimens were similar to a sequence type (ST) 10217 (clonal complex [CC] 10217) isolate genome from Niger, 2015. Multilocus sequencing identified five of seven alleles from one specimen that matched ST-9367, which is represented in the PubMLST database by one carriage isolate from Burkina Faso, in 2011, and belongs to CC10217.

INTERPRETATION

This outbreak featured high attack and case fatality rates. Clinical presentation was broadly consistent with previous meningococcal disease outbreaks, but predominance of gastrointestinal symptoms was unusual compared with previous African meningitis epidemics. The outbreak strain was genetically similar to NmC CC10217, which caused meningococcal disease outbreaks in Niger and Nigeria. CC10217 had previously been identified only in the African meningitis belt.

FUNDING

US Global Health Security.

Detection of evoked acetylcholine release in mouse brain slices

The study of transmitter interactions in reward and motor pathways in the brain, including the striatum, requires methodology to detect stimulus-driven neurotransmitter release events. Such methods exist for dopamine, and have contributed to the understanding of local and behavioral factors that regulate dopamine release. However, factors that regulate release of another key transmitter in these pathways, acetylcholine (ACh), are unresolved, in part because of limited temporal and spatial resolution of current detection methods. We have optimized a voltammetric method for detection of local stimulus-evoked ACh release using enzyme-coated carbon-fiber microelectrodes and fast-scan cyclic voltammetry. These electrodes are based on the detection of H₂O₂ generated by the actions of acetylcholine esterase and choline oxidase, and reliably respond to ACh in a concentration-dependent manner. Methods for enzyme coating were optimized for mechanical stability that allowed for their use in ex vivo brain slices. We report here the first quantitative assessment of extracellular ACh concentration after local electrical stimulation in dorsal striatum in slices from control mice. The selective detection of ACh under these conditions was confirmed by showing that the response detected in the control slices was absent in slices from mice bred to lack ACh synthesis in the forebrain. These electrodes represent a new tool to study ACh and ACh-dopamine interactions with micrometer spatial resolution.

Association of water quality with soil-transmitted helminthiasis and diarrhea in Nueva Santa Rosa, Guatemala, 2010

Improved water quality reduces diarrhea, but the impact of improved water quality on Ascaris and Trichuris, soil-transmitted helminths (STH) conveyed by the fecal-oral route, is less well described. To assess water quality associations with diarrhea and STH, we conducted a cross-sectional survey in households of south-eastern Guatemala. Diarrhea was self-reported in the past week and month. STH was diagnosed by stool testing using a fecal parasite concentrator method. We explored associations between Escherichia coli-positive source water (water quality) and disease outcomes using survey logistic regression models. Overall, 732 persons lived in 167 households where water was tested. Of these, 79.4% (581/732) had E. coli-positive water, 7.9% (58/732) had diarrhea within the week, 14.1% (103/732) had diarrhea within the month, and 6.6% (36/545) tested positive for Ascaris or Trichuris, including 1% (6/536) who also reported diarrhea. Univariable analysis found a statistically significant association between water quality and STH (odds ratio [OR] = 5.1, 95% confidence interval [CI] = 1.1-24.5) but no association between water quality and diarrhea. Waterborne transmission and effects of water treatment on STH prevalence should be investigated further. If a causal relationship is found, practices such as household water treatment including filtration might be useful adjuncts to sanitation, hygiene, and deworming in STH control programs.

Molecular characterization of invasive meningococcal isolates in Burkina Faso as the relative importance of serogroups X and W increases, 2008-2012

Background

Neisseria meningitidis serogroup A disease in Burkina Faso has greatly decreased following introduction of a meningococcal A conjugate vaccine in 2010, yet other serogroups continue to pose a risk of life-threatening disease. Capsule switching among epidemic-associated serogroup A N. meningitidis strains could allow these lineages to persist despite vaccination. The introduction of new strains at the national or sub-national levels could affect the epidemiology of disease.

Methods

Isolates collected from invasive meningococcal disease in Burkina Faso between 2008 and 2012 were characterized by serogrouping and molecular typing. Genome sequences from a subset of isolates were used to infer phylogenetic relationships.

Results

The ST-5 clonal complex (CC5) was identified only among serogroup A isolates, which were rare after 2010. CC181 and CC11 were the most common clonal complexes after 2010, having serogroup X and W isolates, respectively. Whole-genome phylogenetic analysis showed that the CC181 isolates collected during and after the epidemic of 2010 formed a single clade that was closely related to isolates collected in Niger during 2005 and Burkina Faso during 2007. Geographic population structure was identified among the CC181 isolates, where pairs of isolates collected from the same region of Burkina Faso within a single year had less phylogenetic diversity than the CC181 isolate collection as a whole. However, the reduction of phylogenetic diversity within a region did not extend across multiple years. Instead, CC181 isolates collected during the same year had lower than average diversity, even when collected from different regions, indicating geographic mixing of strains across years. The CC11 isolates were primarily collected during the epidemic of 2012, with sparse sampling during 2011. These isolates belong to a clade that includes previously described isolates collected in Burkina Faso, Mali, and Niger from 2011 to 2015. Similar to CC181, reduced phylogenetic diversity was observed among CC11 isolate pairs collected from the same regions during a single year.

Conclusions

The population of disease-associated N. meningitidis strains within Burkina Faso was highly dynamic between 2008 and 2012, reflecting both vaccine-imposed selection against serogroup A strains and potentially complex clonal waves of serogroup X and serogroup W strains.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3247-x) contains supplementary material, which is available to authorized users.

Plasmodium falciparum genetic variation of var2csa in the Democratic Republic of the Congo

BACKGROUND

The Democratic Republic of the Congo (DRC) bears a high burden of malaria, which is exacerbated in pregnant women. The VAR2CSA protein plays a crucial role in pregnancy-associated malaria (PAM), and hence quantifying diversity at the var2csa locus in the DRC is important in understanding the basic epidemiology of PAM, and in developing a robust vaccine against PAM.

METHODS

Samples were taken from the 2013-14 Demographic and Health Survey conducted in the DRC, focusing on children under 5 years of age. A short subregion of the var2csa gene was sequenced in 115 spatial clusters, giving country-wide estimates of sequence polymorphism and spatial population structure.

RESULTS

Results indicate that var2csa is highly polymorphic, and that diversity is being maintained through balancing selection, however, there is no clear signal of phylogenetic or geographic structure to this diversity. Linear modelling demonstrates that the number of var2csa variants in a cluster correlates directly with cluster prevalence, but not with other epidemiological factors such as urbanicity.

CONCLUSIONS

Results suggest that the DRC fits within the global pattern of high var2csa diversity and little genetic differentiation between regions. A broad multivalent VAR2CSA vaccine candidate could benefit from targeting stable regions and common variants to address the substantial genetic diversity.

Measuring ex vivo drug susceptibility in Plasmodium vivax isolates from Cambodia

Background

While intensive Plasmodium falciparum multidrug resistance surveillance continues in Cambodia, relatively little is known about Plasmodium vivax drug resistance in Cambodia or elsewhere. To investigate P. vivax anti-malarial susceptibility in Cambodia, 76 fresh P. vivax isolates collected from Oddar Meanchey (northern Cambodia) in 2013–2015 were assessed for ex vivo drug susceptibility using the microscopy-based schizont maturation test (SMT) and a Plasmodium pan-species lactate dehydrogenase (pLDH) ELISA. P. vivax multidrug resistance gene 1 (pvmdr1) mutations, and copy number were analysed in a subset of isolates.

Results

Ex vivo testing was interpretable in 80% of isolates using the pLDH-ELISA, but only 25% with the SMT. Plasmodium vivax drug susceptibility by pLDH-ELISA was directly compared with 58 P. falciparum isolates collected from the same locations in 2013–4, tested by histidine-rich protein-2 ELISA. Median pLDH-ELISA IC₅₀ of P. vivax isolates was significantly lower for dihydroartemisinin (3.4 vs 6.3 nM), artesunate (3.2 vs 5.7 nM), and chloroquine (22.1 vs 103.8 nM) than P. falciparum but higher for mefloquine (92 vs 66 nM). There were not significant differences for lumefantrine or doxycycline. Both P. vivax and P. falciparum had comparable median piperaquine IC₅₀ (106.5 vs 123.8 nM), but some P. falciparum isolates were able to grow in much higher concentrations above the normal standard range used, attaining up to 100-fold greater IC₅₀s than P. vivax. A high percentage of P. vivax isolates had pvmdr1 Y976F (78%) and F1076L (83%) mutations but none had pvmdr1 amplification.

Conclusion

The findings of high P. vivax IC₅₀ to mefloquine and piperaquine, but not chloroquine, suggest significant drug pressure from drugs used to treat multidrug resistant P. falciparum in Cambodia. Plasmodium vivax isolates are frequently exposed to mefloquine and piperaquine due to mixed infections and the long elimination half-life of these drugs. Difficulty distinguishing infection due to relapsing hypnozoites versus blood-stage recrudescence complicates clinical detection of P. vivax resistance, while well-validated molecular markers of chloroquine resistance remain elusive. The pLDH assay may be a useful adjunctive tool for monitoring for emerging drug resistance, though more thorough validation is needed. Given high grade clinical chloroquine resistance observed recently in neighbouring countries, low chloroquine IC₅₀ values seen here should not be interpreted as susceptibility in the absence of clinical data. Incorporating pLDH monitoring with therapeutic efficacy studies for individuals with P. vivax will help to further validate this field-expedient method.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-2034-2) contains supplementary material, which is available to authorized users.

Increased risk of low birth weight in women with placental malaria associated with P. falciparum VAR2CSA clade

Pregnancy associated malaria (PAM) causes adverse pregnancy and birth outcomes owing to Plasmodium falciparum accumulation in the placenta. Placental accumulation is mediated by P. falciparum protein VAR2CSA, a leading PAM-specific vaccine target. The extent of its antigen diversity and impact on clinical outcomes remain poorly understood. Through amplicon deep-sequencing placental malaria samples from women in Malawi and Benin, we assessed sequence diversity of VAR2CSA’s ID1-DBL2x region, containing putative vaccine targets and estimated associations of specific clades with adverse birth outcomes. Overall, var2csa diversity was high and haplotypes subdivided into five clades, the largest two defined by homology to parasites strains, 3D7 or FCR3. Across both cohorts, compared to women infected with only FCR3-like variants, women infected with only 3D7-like variants delivered infants with lower birthweight (difference: −267.99 g; 95% Confidence Interval [CI]: −466.43 g,−69.55 g) and higher odds of low birthweight (<2500 g) (Odds Ratio [OR] 5.41; 95% CI:0.99,29.52) and small-for-gestational-age (OR: 3.65; 95% CI: 1.01,13.38). In two distinct malaria-endemic African settings, parasites harboring 3D7-like variants of VAR2CSA were associated with worse birth outcomes, supporting differential effects of infection with specific parasite strains. The immense diversity coupled with differential clinical effects of this diversity suggest that an effective VAR2CSA-based vaccine may require multivalent activity.

Anemia Offers Stronger Protection Than Sickle Cell Trait Against the Erythrocytic Stage of Falciparum Malaria and This Protection Is Reversed by Iron Supplementation

Background

Iron deficiency causes long-term adverse consequences for children and is the most common nutritional deficiency worldwide. Observational studies suggest that iron deficiency anemia protects against Plasmodium falciparum malaria and several intervention trials have indicated that iron supplementation increases malaria risk through unknown mechanism(s). This poses a major challenge for health policy. We investigated how anemia inhibits blood stage malaria infection and how iron supplementation abrogates this protection.

Methods

This observational cohort study occurred in a malaria-endemic region where sickle-cell trait is also common. We studied fresh RBCs from anemic children (135 children; age 6–24 months; hemoglobin < 11 g/dl) participating in an iron supplementation trial (ISRCTN registry, number ISRCTN07210906) in which they received iron (12 mg/day) as part of a micronutrient powder for 84 days. Children donated RBCs at baseline, Day 49, and Day 84 for use in flow cytometry-based in vitro growth and invasion assays with P. falciparum laboratory and field strains. In vitro parasite growth in subject RBCs was the primary endpoint.

Findings

Anemia substantially reduced the invasion and growth of both laboratory and field strains of P. falciparum in vitro (~ 10% growth reduction per standard deviation shift in hemoglobin). The population level impact against erythrocytic stage malaria was 15.9% from anemia compared to 3.5% for sickle-cell trait. Parasite growth was 2.4 fold higher after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in erythropoiesis.

Interpretation

These results confirm and quantify a plausible mechanism by which anemia protects African children against falciparum malaria, an effect that is substantially greater than the protection offered by sickle-cell trait. Iron supplementation completely reversed the observed protection and hence should be accompanied by malaria prophylaxis. Lower hemoglobin levels typically seen in populations of African descent may reflect past genetic selection by malaria.

Funding

National Institute of Child Health and Development, Bill and Melinda Gates Foundation, UK Medical Research Council (MRC) and Department for International Development (DFID) under the MRC/DFID Concordat.

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P. falciparum laboratory and field strains invade and grow less efficiently in RBCs from anemic children.

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Deficits in invasion and growth for erythrocytic stage P. falciparum are reversed when RBCs are used from anemic children receiving iron supplementation for 49 and 84 days.

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The population level impact of protection against malaria from anemia was greater than that for sickle-cell trait.

The long-term consequences of anemia are severe, and it is easily treatable. However, concerns remain about the safety of iron supplements, particularly for children in malaria-endemic countries lacking adequate access to health services. We used RBCs from Gambian children before, during, and after 12 weeks of daily iron supplementation for in vitro P. falciparum assays. P. falciparum invasion and growth was decreased in anemic RBCs and increased after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in young RBCs, which the parasite prefers. The parasite growth protection from anemia was substantial, providing greater population level impact than sickle-cell trait.

Estimation of Plasmodium falciparum Transmission Intensity in Lilongwe, Malawi, by Microscopy, Rapid Diagnostic Testing, and Nucleic Acid Detection

Estimates of malaria transmission intensity (MTI) typically rely upon microscopy or rapid diagnostic testing (RDT). However, these methods are less sensitive than nucleic acid amplification techniques and may underestimate parasite prevalence. We compared microscopy, RDT, and polymerase chain reaction (PCR) for the diagnosis of Plasmodium falciparum parasitemia as part of an MTI study of 800 children and adults conducted in Lilongwe, Malawi. PCR detected more cases of parasitemia than microscopy or RDT. Age less than 5 years predicted parasitemia detected by PCR alone (adjusted odds ratio = 1.61, 95% confidence interval = 1.09-2.38, Wald P = 0.02). In addition, we identified one P. falciparum parasite with a false-negative RDT result due to a suspected deletion of the histidine-rich protein 2 (hrp2) gene and used a novel, ultrasensitive PCR assay to detect low-level parasitemia missed by traditional PCR. Molecular methods should be considered for use in future transmission studies as a supplement to RDT or microscopy.

Absence of Association Between Sickle Trait Hemoglobin and Placental Malaria Outcomes

Heterozygous hemoglobin S (HbAS), or sickle trait, protects children from life-threatening falciparum malaria, potentially by attenuating binding of Plasmodium-infected red blood cells (iRBCs) to extracellular ligands. Such binding is central to the pathogenesis of placental malaria (PM). We hypothesized that HbAS would be associated with reduced risks of PM and low birth weight (LBW). We tested this hypothesis in 850 delivering women in southern Malawi. Parasites were detected by polymerase chain reaction in placental and peripheral blood, and placentae were scored histologically for PM. The prevalence of HbAS was 3.7%, and 11.2% of infants were LBW (< 2,500 g). The prevalence of Plasmodium falciparum was 12.7% in placental and 8.5% in peripheral blood; 24.4% of placentae demonstrated histological evidence of P. falciparum HbAS was not associated with reduced prevalence of P. falciparum in placental (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.50-3.23, P = 0.61) or peripheral blood (OR: 2.53, 95% CI: 1.08-2.54, P = 0.03), prevalence of histological PM (OR: 0.97, 95% CI: 0.40-2.34, P = 0.95), or prevalence of LBW (OR: 0.82, 95% CI: 0.24-2.73, P = 0.74). Mean (standard deviation) birth weights of infants born to HbAS (2,947 g [563]) and, homozygous hemoglobin A (2,991 g [465]) mothers were similar. Across a range of parasitologic, clinical, and histologic outcomes, HbAS did not confer protection from PM or its adverse effects.

Long-Lasting Permethrin-Impregnated Clothing Protects Against Mosquito Bites in Outdoor Workers

Outdoor exposure to mosquitoes is a risk factor for many diseases, including malaria and dengue. We have previously shown that long-lasting permethrin-impregnated clothing protects against tick and chigger bites in a double-blind randomized controlled trial in North Carolina outdoor workers. Here, we evaluated whether this clothing is protective against mosquito bites by measuring changes in antibody titers to mosquito salivary gland extracts. On average, there was a 10-fold increase in titer during the spring and summer when mosquito exposure was likely to be the highest. During the first year of the study, the increase in titer in subjects wearing treated uniforms was 2- to 2.5-fold lower than that of control subjects. This finding suggests that long-lasting permethrin-impregnated clothing provided protection against mosquito bites.

Genetic Evidence of Importation of Drug-Resistant Plasmodium falciparum to Guatemala from the Democratic Republic of the Congo

Molecular markers and population genetics were effective tracking tools.

Imported malaria threatens control and elimination efforts in countries that have low rates of transmission. In 2010, an outbreak of Plasmodium falciparum malaria was reported among United Nations peacekeeping soldiers from Guatemala who had recently returned from the Democratic Republic of the Congo (DRC). Epidemiologic evidence suggested that the soldiers were infected in the DRC, but local transmission could not be ruled out in all cases. We used population genetic analyses of neutral microsatellites to determine the outbreak source. Genetic relatedness was compared among parasites found in samples from the soldiers and parasite populations collected in the DRC and Guatemala; parasites identified in the soldiers were more closely related to those from the DRC. A phylogenetic clustering analysis confirms this identification with >99.9% confidence. Thus, results support the hypothesis that the soldiers likely imported malaria from the DRC. This study demonstrates the utility of molecular genotyping in outbreak investigations.

Cntnap4 differentially contributes to GABAergic and dopaminergic synaptic transmission

Although considerable evidence suggests that the chemical synapse is a lynchpin underlying affective disorders, how molecular insults differentially affect specific synaptic connections remains poorly understood. For instance, Neurexin 1a and 2 (NRXN1 and NRXN2) and CNTNAP2 (also known as CASPR2), all members of the neurexin superfamily of transmembrane molecules, have been implicated in neuropsychiatric disorders. However, their loss leads to deficits that have been best characterized with regard to their effect on excitatory cells. Notably, other disease-associated genes such as BDNF and ERBB4 implicate specific interneuron synapses in psychiatric disorders. Consistent with this, cortical interneuron dysfunction has been linked to epilepsy, schizophrenia and autism. Using a microarray screen that focused upon synapse-associated molecules, we identified Cntnap4 (contactin associated protein-like 4, also known as Caspr4) as highly enriched in developing murine interneurons. In this study we show that Cntnap4 is localized presynaptically and its loss leads to a reduction in the output of cortical parvalbumin (PV)-positive GABAergic (γ-aminobutyric acid producing) basket cells. Paradoxically, the loss of Cntnap4 augments midbrain dopaminergic release in the nucleus accumbens. In Cntnap4 mutant mice, synaptic defects in these disease-relevant neuronal populations are mirrored by sensory-motor gating and grooming endophenotypes; these symptoms could be pharmacologically reversed, providing promise for therapeutic intervention in psychiatric disorders.

Field evaluation of a real-time fluorescence loop-mediated isothermal amplification assay, RealAmp, for the diagnosis of malaria in Thailand and India

BACKGROUND

To eliminate malaria, surveillance for submicroscopic infections is needed. Molecular methods can detect submicroscopic infections but have not hitherto been amenable to implementation in surveillance programs. A portable loop-mediated isothermal amplification assay called RealAmp was assessed in 2 areas of low malaria transmission.

METHODS

RealAmp was evaluated in 141 patients from health clinics in India (passive surveillance) and in 127 asymptomatic persons in Thailand (active surveillance). The diagnostic validity, precision, and predictive value of RealAmp were determined using polymerase chain reaction (PCR) as the reference method. A pilot study of RealAmp was also performed on samples from patients presenting at a Thai health center.

RESULTS

A total of 96 and 7 positive cases were detected in India and Thailand, respectively, via PCR. In comparison with nested PCR, the sensitivity and specificity of RealAmp in India were 94.8% (95% confidence interval [CI], 88.3%-98.3%) and 100% (95% CI, 92.1%-100%), respectively, with correct identification of all 5 Plasmodium vivax cases. In Thailand, compared with pooled real-time PCR, RealAmp demonstrated 100% sensitivity (95% CI, 59.0%-100%) and 96.7% specificity (95% CI, 91.7%-99.1%). Testing at the health center demonstrated RealAmp's potential to serve as a point-of-care test with results available in 30-75 minutes.

CONCLUSION

RealAmp was comparable to PCR in detecting malaria parasites and shows promise as a tool to detect submicroscopic infections in malaria control and elimination programs worldwide.

Comparative population structure of Plasmodium falciparum circumsporozoite protein NANP repeat lengths in Lilongwe, Malawi

Humoral immunity to Plasmodium falciparum circumsporozoite protein is partly mediated by a polymorphic NANP tetra-amino acid repeat. Antibody response to these repeats is the best correlate of protective immunity to the RTS,S malaria vaccine, but few descriptions of the natural variation of these repeats exist. Using capillary electrophoresis to determine the distribution of NANP repeat size polymorphisms among 98 isolates from Lilongwe, Malawi, we characterised the diversity of P. falciparum infection by several ecological indices. Infection by multiple distinct variants was common, and 20 distinct repeat sizes were identified. Diversity of P. falciparum appeared greater in children (18 variants) than adults (12 variants). There was evidence of genetic distance between different geographic regions by Nei's Standard Genetic Distance, suggesting parasite populations vary locally. We show that P. falciparum is very diverse with respect to NANP repeat length even on a local level and that diversity appears higher in children.

Plasmodium vivax isolates from Cambodia and Thailand show high genetic complexity and distinct patterns of P. vivax multidrug resistance gene 1 (pvmdr1) polymorphisms

Plasmodium vivax accounts for an increasing fraction of malaria infections in Thailand and Cambodia. We compared P. vivax genetic complexity and antimalarial resistance patterns in the two countries. Use of a heteroduplex tracking assay targeting the merozoite surface protein 1 gene revealed that vivax infections in both countries are frequently polyclonal (84%), with parasites that are highly diverse (HE = 0.86) but closely related (GST = 0.18). Following a history of different drug policies in Thailand and Cambodia, distinct patterns of antimalarial resistance have emerged: most Cambodian isolates harbor the P. vivax multidrug resistance gene 1 (pvmdr1) 976F mutation associated with chloroquine resistance (89% versus 8%, P < 0.001), whereas Thai isolates more often display increased pvmdr1 copy number (39% versus 4%, P < 0.001). Finally, genotyping of paired isolates from individuals suspected of suffering relapse supports a complex scheme of relapse whereby recurrence of multiple identical variants is sometimes accompanied by the appearance of novel variants.

Neuromuscular blocking effect of fluoxetine and its interaction with rocuronium

As selective serotonin reuptake inhibitors have an inhibitory effect on nicotinic acetylcholine receptors, they may affect the neuromuscular transmission and interact with neuromuscular blockers. This study was designed to observe the effect of fluoxetine on neuromuscular transmission and its interaction with rocuronium using the rat phrenic nerve hemidiaphragm and rabbit head drop methods. Rat phrenic nerve hemidiaphragms were mounted and stimulated using a train of four pulses (TOF). The effect of fluoxetine was studied on both indirectly and directly stimulated basal twitch responses by plotting cumulative dose response curves (DRCs). DRCs of rocuronium were obtained in the absence, and presence of 5 μm and 20 μm fluoxetine to study its interaction. ED5 , ED50 and ED95 values of rocuronium DRCs in absence and presence of fluoxetine were calculated. Fluoxetine significantly inhibited twitch responses in both indirect and directly stimulated preparations. Fluoxetine (20 μm) caused an increase in the potency of rocuronium such that the ED50 and ED95 values of rocuronium DRCs were significantly decreased. Partially inhibited twitch responses by fluoxetine (100 μm) were not reversed by neostigmine (3.3 μm) or 3,4 diaminopyridine (0.25 μm). Rabbits were given fluoxetine 0.25 mg kg(-1) and 1 mg kg(-1) orally for 15 days, and on 15th day, rocuronium infusion was given, and time for head drop was recorded. The time of head drop was significantly reduced in fluoxetine pretreated as compared to control group. Fluoxetine blocks the neuromuscular transmission and increases the potency of rocuronium-induced neuromuscular block.

Real-time loop-mediated isothermal amplification (RealAmp) for the species-specific identification of Plasmodium vivax

Plasmodium vivax infections remain a major source of malaria-related morbidity and mortality. Early and accurate diagnosis is an integral component of effective malaria control programs. Conventional molecular diagnostic methods provide accurate results but are often resource-intensive, expensive, have a long turnaround time and are beyond the capacity of most malaria-endemic countries. Our laboratory has recently developed a new platform called RealAmp, which combines loop-mediated isothermal amplification (LAMP) with a portable tube scanner real-time isothermal instrument for the rapid detection of malaria parasites. Here we describe new primers for the detection of P. vivax using the RealAmp method. Three pairs of amplification primers required for this method were derived from a conserved DNA sequence unique to the P. vivax genome. The amplification was carried out at 64°C using SYBR Green or SYTO-9 intercalating dyes for 90 minutes with the tube scanner set to collect fluorescence signals at 1-minute intervals. Clinical samples of P. vivax and other human-infecting malaria parasite species were used to determine the sensitivity and specificity of the primers by comparing with an 18S ribosomal RNA-based nested PCR as the gold standard. The new set of primers consistently detected laboratory-maintained isolates of P. vivax from different parts of the world. The primers detected P. vivax in the clinical samples with 94.59% sensitivity (95% CI: 87.48-98.26%) and 100% specificity (95% CI: 90.40-100%) compared to the gold standard nested-PCR method. The new primers also proved to be more sensitive than the published species-specific primers specifically developed for the LAMP method in detecting P. vivax.

Dried Plasmodium falciparum-infected samples as positive controls for malaria rapid diagnostic tests

BACKGROUND

Rapid diagnostic tests (RDTs) are central to fulfilling the WHO's recommendation for parasitologic confirmation of all suspected cases of malaria. RDT performance may be compromised when exposed to the high temperature conditions typical of most malaria endemic regions. However, a systematic method to monitor RDT quality and performance in endemic countries is lacking at the present time. Current methods to monitor RDT performance in the field include comparing results from RDTs to diagnoses made by light microscopy and observing health workers perform tests. These methods are not substitutes for direct quality control. In this study, the suitability of dried Plasmodium falciparum-infected blood as quality control samples for malaria RDTs was evaluated.

METHODS

Three cultured strains of P. falciparum at 200 and 2,000 parasites/μl were tested on 10 brands of RDT. After baseline testing to determine initial reactivity, aliquots of parasite-infected blood were air dried, stored at 35°C, room temperature (~25°C) or 4°C for one, four and 12 weeks and were then tested on the 10 RDTs after rehydration. Extended stability testing of dried blood stored at 4°C was done using P. falciparum strain 3D7 at 1,000 and 2,000 parasites/μl.

RESULTS

All dried blood samples at 2,000 parasites/μl retained reactivity (100% sensitivity) at all three temperatures and time points for all nine RDT brands that detect histidine-rich protein-2 (HRP2). The dried blood samples with 200 parasites/μl were detected by six of the nine HRP2-based RDTs at all storage temperatures and time points. The sensitivity for two of the three remaining HRP2-based RDTs was 100% up to four weeks of storage at all temperatures but dropped to 87.5% at week 12. Of the four RDTs that detect plasmodium lactate dehydrogenase (pLDH) in a pan-specific manner, alone or in combination with HRP2, the detection of pLDH in samples with 2,000 parasites/μL was 100% for two RDTs and 80% for the other two RDTs. The mean level for detection of pLDH at 200 parasites/μl was low (29%), with a range of 0% to100%, which was partly attributable to weak initial baseline reactivity. Reactivity of dried 3D7 at 1,000 and 2,000 parasites/μl stored at 4°C was retained at 100% for up to 52 weeks for both HRP2 and pLDH.

CONCLUSIONS

In the absence of native or recombinant positive control antigens, well-standardized P. falciparum-infected dried blood samples can be used as positive control samples for monitoring RDT performance, particularly with HRP2-detecting tests.

Dopamine release in the basal ganglia

Dopamine (DA) is a key transmitter in the basal ganglia, yet DA transmission does not conform to several aspects of the classic synaptic doctrine. Axonal DA release occurs through vesicular exocytosis and is action potential- and Ca²⁺-dependent. However, in addition to axonal release, DA neurons in midbrain exhibit somatodendritic release by an incompletely understood, but apparently exocytotic, mechanism. Even in striatum, axonal release sites are controversial, with evidence for DA varicosities that lack postsynaptic specialization, and largely extrasynaptic DA receptors and transporters. Moreover, DA release is often assumed to reflect a global response to a population of activities in midbrain DA neurons, whether tonic or phasic, with precise timing and specificity of action governed by other basal ganglia circuits. This view has been reinforced by anatomical evidence showing dense axonal DA arbors throughout striatum, and a lattice network formed by DA axons and glutamatergic input from cortex and thalamus. Nonetheless, localized DA transients are seen in vivo using voltammetric methods with high spatial and temporal resolution. Mechanistic studies using similar methods in vitro have revealed local regulation of DA release by other transmitters and modulators, as well as by proteins known to be disrupted in Parkinson's disease and other movement disorders. Notably, the actions of most other striatal transmitters on DA release also do not conform to the synaptic doctrine, with the absence of direct synaptic contacts for glutamate, GABA, and acetylcholine (ACh) on striatal DA axons. Overall, the findings reviewed here indicate that DA signaling in the basal ganglia is sculpted by cooperation between the timing and pattern of DA input and those of local regulatory factors.

Genetic backgrounds of the Plasmodium falciparum chloroquine resistant transporter (pfcrt) alleles in Pakistan

Chloroquine (CQ) resistance in Plasmodium falciparum has been associated with point mutations in the P. falciparum CQ resistance transporter gene (pfcrt). Previous studies have shown 4-5 independent origins for CQ resistant pfcrt alleles globally, two in South America, one each in Southeast Asia, Papua New Guinea (PNG) and Philippines. In Asia, at least two different alleles corresponding to amino acids 72-76 (CVIET and SVMNT) have been found. The CVIET allele originated in Southeast Asia and then spread to Asia and Africa as well. The SVMNT allele, originating from PNG, has been found in India. This study was undertaken to investigate the genetic background of the CQ resistant pfcrt haplotypes in Pakistan. We genotyped microsatellite markers surrounding the pfcrt gene (six different markers at -12.3, -4.8, -1, 1.5, 3.9, 18.8 kb) in 114 clinical isolates of P. falciparum collected from different regions in Pakistan. Microsatellite analysis showed a significant reduction in genetic variation among the mutant SVMNT pfcrt alleles when compared to wild type alleles. The predominant SVMNT haplotype found in this study shared the same microsatellite haplotype found in both PNG and India. Two isolates with CVIET haplotypes showed similar microsatellite background to those found in Africa and Asia. In conclusion, this study suggests that CQ resistant SVMNT haplotypes in India and Pakistan have a common ancestral origin similar to that of Papua New Guinean isolates.

Synthesis and microbial studies of (4-oxo-thiazolidinyl) sulfonamides bearing quinazolin-4(3H)ones

2-[(2,6-Dichlorophenyl)amino]phenylacetic acid (A) on reaction with thionyl chloride gave corresponding acid chloride (B). A series of (4-oxo-thiazolidinyl)sulfonamides of quinazolin-4(3H)ones (4a-l) were prepared from Schiff bases (3a-l) of 2-[2-(2,6-dichlorophenyl)amino]phenylmethyl-3-[(4-aminophenyl)sulfonamido-1-yl]quinazolin-4(3H)one (D) and substituted aromatic aldehyde. Newly synthesized compounds have been examined on the basis of elemental analysis, IR, 1H NMR and 13C NMR spectra. Antibacterial activity (minimum inhibitory concentration - MIC) against Gram-positive (S. aureus & S. pyogeneus) and Gram-negative (P. aeruginosa and E. coli) bacteria, as well as antifungal acivities (MIC) against C. albicans, A. niger and A. clavatus were determined by broth dilution method. Some of the compounds were endowed with a remarkable antibacterial as well as antifungal acivities.

Synthesis and antimicrobial activity of 3-(1,3,4-Oxadiazol-2-yl)quinazolin-4(3H)-ones

In attempt to find new pharmacologically active molecules, we report here the synthesis and in vitro antimicrobial activity of various 3-(1,3,4-oxadiazol-2-yl)-quinazolin-4(3H)-ones. The antimicrobial activity of title compounds were examined against two gram positive bacteria (S. aureus, S. pyogenes), two gram negative bacteria (E. coli, P. aeruginosa) and three fungi (C. albicans, A. niger, A. clavatus) using the broth microdilution method. Some derivatives bearing a bromo or iodo group exhibited very good antimicrobial activity.

Immunocytochemical identification of proteins involved in dopamine release from the somatodendritic compartment of nigral dopaminergic neurons

We examined the somatodendritic compartment of nigral dopaminergic neurons by immunocytochemistry and confocal microscopy, with the aim of identifying proteins that participate in dopamine packaging and release. Nigral dopaminergic neurons were identified by location, cellular features and tyrosine hydroxylase immunoreactivity. Immunoreactive puncta of vesicular monoamine transporter type 2 and proton ATPase, both involved in the packaging of dopamine for release, were located primarily in dopaminergic cell bodies, but were absent in distal dopaminergic dendrites. Many presynaptic proteins associated with transmitter release at fast synapses were absent in nigral dopaminergic neurons, including synaptotagmin 1, syntaxin1, synaptic vesicle proteins 2a and 2b, synaptophysin and synaptobrevin 1 (VAMP 1). On the other hand, syntaxin 3, synaptobrevin 2 (VAMP 2) and SNAP-25-immunoreactivities were found in dopaminergic somata and dendrites Our data imply that the storage and exocytosis of dopamine from the somatodendritic compartment of nigral dopaminergic neurons is mechanistically distinct from transmitter release at axon terminals utilizing amino acid neurotransmitters.

Sinus of Valsalva fistula with quadricuspid aortic valve, a first reported association

Quadricuspid aortic valve and sinus of Valsalva fistula are rare congenital anomalies. We report the first case of association of these two congenital anomalies in an adult patient and the important role of Magnetic Resonance Imaging (MRI) in establishing and confirming the correct diagnosis and helping in planning the treatment.

Masquerade: a malignant arrhythmia masquerading as benign

Pseudoatrial flutter has been reported to have benign causes, but this is the first report of a malignant arrhythmia presenting as a benign arrhythmia. An 82 year old patient presented with ventricular tachycardia and electrical artefact appearing as atrial flutter. In this case, comparing the morphology of the QRS complexes in the rhythm strip with those in lead II showed the arrhythmia to be ventricular in origin and points to the importance of comparing all leads of the ECG before arriving at a diagnosis.

Follow up of 318 cases of diabetes mellitus

Ignorance, apathy, desire to get free advice, investigation and treatment is prevalent in diabetics. Most diabetics (69.63%) are uncontrolled whether on diet, single oral drug or combination of oral drugs or insulin. Ischemic heart disease was commonest complication. Neuritis was present in the one fourth of the followed up cases and was more prevalent in uncontrolled cases. Hypertension increases with the duration of diabetes and was twice more prevalent after duration of more than 5 years. Eye changes were present in about 50% of the people examined. Abnormality increases with the duration of diabetes.

GERD like symptoms as seen in a village

Twenty cases of protozoal infection presented with symptoms suggesting GERD. Treatment with antacids and H2 blockers was unsuccessful in giving them relief. As they had also protozoal infection, treatment with anti-protozoal drugs gave them complete relief in the follow up period of one year after the end of treatment. Hence we have named these conditions simulating peptic ulcer GERD as pseodogerd or protozoal GERD. It is suggested that the person presenting with the symptoms of GERD in our area should be investigated for protozoal infection or should be given treatment of protozoal infection rather than that of peptic ulcers. It is also suggested that the length of treatment of protozoal infection should not be less than one month and not for three or 7 days as suggested in western text books.