Anopheles culicifacies Giles: a release-recapture experiment with cohorts of known age with implications for malaria epidemiology and genetical control in Pakistan

A mark-release-recapture experiment with the progeny of wild collected Anopheles culicifacies was performed during the monsoon season of 1978 at the village of Khano-Harni, a malarious area situated in Lahore District, Punjab Province, Pakistan. The recapture rates of males and females released at breeding and resting sites were statistically comparable and totalled 8·0% for females and 5·9% for males collected resting in houses and cattle sheds. Mating occurred mostly on the night following the evening of release when the females were about two days old. Insemination rates for females released at resting and breeding sites were statistically comparable. The initial gonotrophic cycle required four days; subsequent cycles occurred at two-day intervals with re-feeding on the same night as oviposition. Constant daily survivorship estimated from the decline in recaptures per day was 0·568 for females and 0·676 for males. Female survivorship estimated by vertical age grading methods ranged from 0·472 to 0·820. Horizontal life tables were calculated from the decline in recaptures and from vertical age-grading techniques and indicated that female or male life expectancy at emergence was less than 2·5 days. Population size was calculated using the Lincoln Index, Jackson's positive and negative methods and Ito's modification of Jackson's positive method and averaged from 1045·5 to 1049·6 females and from 449·1 to 1323·7 males. The relationship of these results to malaria transmission and genetical control is discussed.     

Toxicity of insecticides to tsetse flies

New insecticides have been evaluated for toxicity to tsetse flies and compared with organochlorine compounds currently in use. The most toxic compounds and their estimated median lethal doses in nanograms per fly by topical application in solution to teneral Glossina austeni were: resmethrin 4, fenthion 8, dieldrin 10, propoxur 12, chlorfenvinphos 12, tetrachlorvinphos 20, and dichlorvos 20. There was little variation in the susceptibility of teneral male and female flies, young fed flies, and fed stud males with all the compounds tested (dieldrin, resmethrin, tetrachlorvinphos, bromophos, and propoxur) and increased tolerance in old fed pregnant flies occurred only with dieldrin and resmethrin. There was also little variation in the susceptibility of teneral flies of the two species G. austeni and G. morsitans. In contact toxicity tests with water dispersible powder deposits on plywood, propoxur was highly active initially but lost its effectiveness after only a few weeks, whereas tetrachlorvinphos was less active initially but more persistent.     

10. Effect of insecticide-treated bed nets on the dynamics of multiple Plasmodium falciparum infections

The rates of acquisition and loss of individual genotypes belonging to the FC27 family of the Plasmodium falciparum merozoite surface protein 2 (msp2) gene were studied in 120 children aged 5 months to 2·5 years, in a randomized controlled trial of insecticide-treated bed nets (ITNs) in Kiberege village, Tanzania. Analysis of longitudinal changes in positivity for individual alleles in samples collected at intervals of one month indicated that the average duration of infections, allowing for undetected parasite genotypes, was 73 d in those aged <18 months and 160 d in children aged ≥18 months, consistent with a shift from acute to chronic infection with age. Overall, 51% of genotypes infecting the host were estimated to be detected by polymerase chain reaction-restriction fragment length polymorphism analysis in any one sample of 0·5 μL of packed peripheral blood cells. In children less than 18 months old this sensitivity was 61% (SE = 6%) compared with 41% (SE = 6%) in older children. Conversely, the rate of appearance of new parasite genotypes was higher in children <18 months of age than in older children, but this partly reflected the difference in sensitivity. The overall incidence of new infections was estimated to be reduced by 17% in ITN users. There was no statistically significant difference between users and non-users in observed infection multiplicity, sensitivity, recovery rate, or estimated infection rates for individual alleles. This suggests that, in areas of high P. falciparum endemicity, ITNs have little effect on the establishment of chronic malaria infection.     

Contrasting epidemiology of shigellae dysenteriae and shigellae flexneri,Dacca

To characterize the epidemiological contrast between Shigella dysenteriae type 1, Sh. flexneri and dysentery-like control families, a 10-day follow-up study has been conducted in Dacca areas where Sh. flexneri and Sh. dysenteriae type 1 were the two most prevalent types.In children (0–9), the secondary infection rates were 29·3% in Sh. dysenteriae type 1, 24% in Sh. flexneri and 10·6% in the control group. The overall secondary infection rates were 20·4, 21·2 and 6·1% and secondary case rates were 13·3, 4·3 and 2·0% respectively for the three groups. In the Sh. flexneri group, secondary cases in infected adults were nil, but 41·1% of the adults infected with Sh. dysenteriae type 1 developed symptoms. Over 2% of the contacts of Sh. dysenteriae type 1 and none from the Sh. flexneri needed to be kept in hospital.Mixed infection, in contacts of all the three types ranged from 4·6 to 6·4%. The undiagnosed diarrhoea (over 14%) exceeded the secondary cases in all groups.In each case, secondary infection rates were higher when the first cases of the families, were children aged below 10 or females aged 10 and over, than when the index cases were males 10 years old or more. In Sh. dysenteriae type 1, secondary spread continued up to the last day of follow-up. In Sh. flexneri, it stopped two days earlier.Users of water from both open and closed sources and users of open latrines had higher attack rates than did those who used closed water sources and closed latrines. In all cases the poorest group had higher secondary attack rates. Sh. dysenteriae type 1 was 98% resistant to tetracycline and 93·6% to streptomycin, while over 20% of Sh. flexneri were resistant to tetracycline and 50% to streptomycin. Both the strains were 100% sensitive to kanamycin and ampicillin at the time of this study 1973.     

Dracontiasis in western Rajasthan, India

Epidemiology of the guinea-worm, Dracunculus medinensis, was studied in relation to the sex, age, food and drinking water of the inhabitants of 50 villages of four districts located in the Great Indian Desert region of western Rajasthan, India. In all, 21,616 subjects (11,794 male, 9,822 female), belonging to 3,808 families were examined. 78·0% (39 of 50) of villages, 18·1% (691 of 3,808) of families and 4·5% (985 of 21,616 subjects) of the population (5·6% male, 3·3% female) were infected. Exposed to suspect water supply, 13,667 people were estimated to be at risk at any time. In the infected villages the prevalence rate varied from 0·2% to 24·7%. The difference in the incidence of the infection in the two sexes was statistically significant. The working age group (20 to 40 years old) exhibited the maximum frequency of infection. The largest number of first infections was observed in people between 20 and 30 years old. Reinfection, with a maximum in subjects between 20 and 30 years old, was frequent in all age groups and, apparently, the host did not acquire immunity against subsequent infection. Non-vegetarian communities appeared to be more prone to guinea-worm infection than vegetarian communities. Pond water was found to be the major source of infection. Except for certain dubious indigenous methods, no treatment worth the name is available. The disease was prevalent during the months late March to early July and thus coincides with the farming season. In addition to crop losses and personal agony, the total loss due to dracontiasis could be about Rs. 10·5 crores annually.     

Type I pili,CsuA/B and FimA induce a protective immune response against Acinetobacter baumannii

BackgroundAcinetobacter baumannii, a nosocomial pathogen, is considered as a common cause of hospital and community-acquired infections. Emerging multidrug-resistance in this pathogen followed by subsequent problems in treatment has been increasing to alarming levels that warrant investigation of new therapeutic approaches. One strategy to reduce antibiotic resistance is to use of vaccines. Although there is no vaccine currently in development for this pathogen, different attempts have been made to develop one.MethodsIn this study, we used two different recombinant pilus proteins (CsuA/B and FimA) either singly or in combination to evaluate protective efficacy against A. baumannii in lethal and sub-lethal murine sepsis models.FindingsActive immunization with recombinant proteins in combination elicited high levels of IgG antibody after the first immunization and provided 62% (five of eight mice; p < 0·001) protection against a lethal dose (1·2 × 10⁶ CFU) of A. baumannii along with efficient clearance of bacteria in internal organs viz. spleen, liver, and lungs at sub-lethal challenge. Immunization with CsuA/B alone conferred partial protection as demonstrated by low survival rate (three [37%] of eight mice; p < 0·05) after lethal challenge and reduction of bacteria in internal organs of the mice after 24 h post-sub-lethal infection. Immunization with FimA, in comparison to CsuA/B, showed better protection (four [50%] of eight mice; p < 0·01) and reduction in CFU after 14 h.InterpretationOur results showed that pilus proteins in combination as a single immunogen could potentially impart protection against A. baumannii.FundingShahed University.     

The hosts and trypanosome infection rates of Glossina pallidipes in the Lambwe and Roo valleys

Several thousand Glossina pallidipes flies were dissected to determine trypanosome infection rates in the Lambwe Valley and to collect information on the hosts of this tsetse. A total of 1 450 (19.3%) flies had mature trypanosome infections but the rate varied between 9.6% and 30.9% in the Lambwe Valley. In the Roo Valley the rate was 19.7-28.6%. Blood-meal squashes from tsetse collected in the Roo Valley and Obaluanda areas and in the Ruma, Otuok, and Rari thickets showed that the important hosts were bushbuck and bushpig. Analyses showed that T. brucei subgroup infection rates in the Roo Valley near two small dams (3.7% and 4.0%) were higher than might have been expected; in another part of the Roo Valley the rate was only 0.8%. To account for such a large difference it is concluded that the dissecting techniques were probably at fault, leading to an overestimation of T. brucei subgroup infection rates in the Roo Valley tsetse. In the main Lambwe Valley there was a tendency for the tsetse trypanosome infection rates to increase towards the southern part of the valley where game animals were numerous and readily available to tsetse in the favourable thicket habitats.     

Race-linked differences in serum concentrations of dapsone,monoacetyldapsone and pyrimethamine during malaria prophylaxis

Serum concentrations of dapsone (DDS), monoacetyldapsone (MADDS), the principal acetylated metabolite of DDS, and pyrimethamine (PYR) were measured in 55 Caucasian adults (31 males, 24 females) and 159 Papua New Guinean adults (140 males, 19 females) following the oral administration of Folaprim^R (100mg DDS; 12·5mg PYR). Blood samples were collected at mean sampling times of eight hours after medication and 18 hours before the next weekly dose for malaria prophylaxis. Clearance of DDS and MADDS from serum were significantly faster (p<0·001) in Caucasians than in Papua New Guineans. Significantly lower (p<0·001) serum concentrations of PYR were found in Papua New Guineans than in Caucasians at both sampling times, an observation which may reflect differences in the bioavailability of PYR between the two racial groups. The theoretical implications of these results are that Caucasians may be more susceptible to PYR-resistant Plasmodium falciparum malaria than Papua New Guineans whilst Papua New Guineans may be more susceptible to P. vivax malaria than Caucasians.     

不同年龄及性别家蝇对凯素灵及奋斗呐药膜敏感性比较

用强迫接触法测定玻璃上的凯素灵药膜（０．２５及２．５ｍｇ／ｍ２）及奋斗呐药膜（１及１０ｍｇ／ｍ２）对９个年龄雌、雄家蝇的ＫＴ５０及２４ｈ死亡率。１～７天龄家蝇ＫＴ５０随年龄增加而增加；＞７天龄家蝇ＫＴ５０较稳定，并有随年龄增加而减少之趋势。相同处理的雄虫ＫＴ５０均小于雌虫。２．５ｍｇ／ｍ２凯素灵及１０ｍｇ／ｍ２奋斗呐处理家蝇死亡率均为１００％，０．２５ｍｇ／ｍ２凯素灵处理４～１０天蝇死亡率最低，相同药膜处理＞１０天龄家蝇及１ｍｇ／ｍ２奋斗呐处理家蝇死亡率随年龄增加而增加。且雄虫死亡率高于雌虫。     

A comparison of the use of povidone-iodine and chlorhexidine in the prophylaxis of postoperative wound infection

Povidone-iodine and chlorhexidine surgical scrub and skin preparation solutions were assessed by comparing postoperative wound infection rates in a prospective, randomized study of 866 patients.The frequency of wound infection overall, as agreed by two observers, was 14·8 per cent in the povidone-iodine group and 9·7 per cent in the chlorhexidine group (P = 0·03) at the time of patients' discharge from hospital. The difference between the compounds was not significant at a ‘standard’ observation period of three to four days after operation. There were significantly fewer infections with chlorhexidine than with povidone-iodine in operations on the biliary tract and in ‘clean’ non-abdominal operations, but there were more infections (not significantly so) with chlorhexidine than with povidoneiodine in large bowel surgery, other laparotomies and in operations on hernia, genitalia and varicose veins. The differences in bacterial isolates from wounds tended to follow the above patterns.We conclude that, on the evidence of this study, there is no overwhelming case for using one compound rather than the other as an all-purpose preparation and scrub.     

Chlamydia and Gonorrhea Prevalence and Treatment in Detained Youths: Strategies for Improvement

PurposeAdolescents and young adults have the highest prevalence of sexually transmitted infections (STIs), accounting for more than 50% of all reported infections. An especially high-risk group includes adolescents in juvenile or correctional facilities.MethodsThis retrospective analysis was conducted at the only juvenile detention facility in the State of Hawai'i from 2014 to 2017. Adolescents aged 12–17 years were offered STI screening and/or presumptive treatment at the time of medical evaluation.ResultsOf 2,208 adolescents offered voluntary testing, 461 males and 372 females agreed to be tested for Chlamydia trachomatis and Neisseria Gonorrhea. Acceptance did not vary by age; females chose testing more often than males (67.4% vs. 27.8%; p < .0001). Females were also more likely to accept presumptive treatment (22.8% vs. 8.8%; p < .0001). In tested youth, STIs were prevalent in 24% of females and 10% of males. Before leaving the detention facility, only half the STIs in females and only 39% of male STI infections had been treated.ConclusionsThere was a high prevalence of STIs in both males and females admitted to this juvenile detention facility, with fewer than half the documented infections being treated before discharge. This indicates a need for universal and timely testing to allow the treatment of those infected. If for whatever reason rapid testing cannot be obtained, presumptive treatment offers a pragmatic approach to treatment and infection control.     

A preliminary survey of malnutrition and helminthiasis among school-children in one mountain and one lowland ujamaa village in Northern Tanzania

The nutritional status, parasite prevalence and immediate skin hypersensitivity to Ascaris and Schistosoma antigens were determined for 185 schoolchildren living in two ujamaa villages in Northern Tanzania.In the lowland village of Kwamsisi the parasite ova found were Schistosoma haematobium (53·8%), Ascaris (26·0%) and hookworm (24·7%). 57·5% of the children examined were regarded as malnourished, being less than 80% of their expected weight for age.In the mountain village of Ubiri the parasite prevalence rates were 15·2% for Schistosoma haematobium, 1·6% for S. Mansoni, 65·2% Ascaris and 24·1% hookworm. Malnutrition was found in 81·9% of the boys and in 41·2% of the girls. This sex difference is considered to be due to the physiological effects of living in a hilly environment.Correlation between malnutrition and multiple infections of Ascaris, hookworm and Schistosoma gave a chi-square value of 5·972 (p = 0·02). All other statistical comparisons between parasite prevalence and nutritional status were insignificant.Immediate skin hypersensitivity tests proved unreliable with 23·3% false negatives (negative skin test with parasite ova found). The serum IgE levels were extremely high with a mean of 3174 units per ml suggesting that the immune mechanisms were not retarded by undernutrition.     

Bancroftian filariasis in coastal north Trinidad,West Indies: intensity of transmission by Culex quinquefasciatus

The intensity of transmission of Wuchereria bancrofti was measured in a coastal community in north Trinidad where 15% of the residents were microfilaraemic. The only significant vector, Culex quinquefasciatus, was studied in detail to determine seasonal abundance, longevity, infection and infectivity rates. Only 2·1% of the indoor biting population and 7·0% of the indoor resting population were infected. The daily mortality rate of the vector increased with age from 27% at four days to 44 to 47% at 12 days and is considered to be an important factor contributing to the low infectivity rate (0·1%). The mean number of C. quinquefasciatus bites received by a resident of the village during the year of observation was estimated to be 17,948 of which 14 were from mosquitoes harbouring infective larvae of W. Bancrofti. The results from similar studies elsewhere are outlined, but the need for standardization of procedures is emphasized before more reliable comparisons can be made.     

Cryopreservation of viable Giardia intestinalis trophozoites

A technique is described for the cryopreservation of Giardia intestinalis trophozoites. The most satisfactory results were obtained when organisms were preserved with either 7·5 or 10% dimethyl sulphoxide (Me₂SO) and cooled using a liquid nitrogen controlled freezer. Under these conditions more than 70% of organisms were motile after thawing. Lower recovery rates were obtained using glycerol as the cryopreservant or when samples were placed directly into a ?70 °C refrigerator to cool. Cultures were successfully re-established from material cooled under controlled conditions using either 7·5% Me₂SO or glycerol as the cryopreservant. However, the former had an initial generation time of 12·0 hours compared to 24·5 hours for the latter.     

Distribution of microfilariae in Guatemalans with onchocerciasis

Ten Simulium ochraceum were allowed to feed at 10 different sites on 12 Guatemalans with onchocerciasis, and skin snips were taken from six of these sites. Numbers of microfilariae (mff) ingested by the flies and mff emerging from skin snips were highly correlated and showed that concentrations were greatest on the torso and decreased peripherally. S. ochraceum ingested the number of mff present in 1·0 mg or under 1·5 mm² of skin. Numbers of mff in skin snips from the head, shoulder and upper arm correlated with over-all levels of infection but were frequently negative in subjects with light infections. Two or more skin snips were best able to detect and quantify infections.     

Human papillomavirus vaccine uptake among males 11–26 years in United States: Findings from the National Health and Nutrition Examination Survey, 2011–2012

Anogenital human papillomavirus (HPV) infection is the leading sexually transmitted infection in the United States. In October 2011, the quadrivalent HPV vaccine (HPV4) was recommended for males in the U.S. We analyzed a subsample of 11–26 year old (N = 1012) males, from the National Health and Nutritional Examination Survey 2011–2012 dataset, to examine HPV vaccine uptake. The initiation rates in the 11–17 years and the 18–26 years age-groups were 10.7% (95% confidence interval (CI): 8.09–16.6%) and 5.5% (95%CI: 3.1–9.5%) respectively. The corresponding HPV vaccine completion rates were 39.3% (16.7–67.7%) for the 11–17 year old males and 59.1% (37.2–77.6) for the 18–26-year-old males. Despite a slight increase, HPV vaccine uptake remained low among males. These findings can help in HPV vaccination policy in the United States, with a focus on informational messages directed toward young males and their parents in order to increase uptake of HPV vaccine.     

Long-term efficacy of single-dose oral treatment in schistosomiasis haematobium

A two-year follow-up was conducted in children who had been the subjects of a six-month double-blind trial in the single-dose treatment of Schistosoma haematobium infection. The trial had assessed therapeutic efficacy of three oral preparations—praziquantel 40 mg/kg, metrifonate 10 mg/kg, and the “combination” (concurrent niridazole 25 mg/kg and metrifonate 10 mg/kg administration).Reduction in urinary egg excretion remained high up to follow-up at two years, based on a comparison of pre- and post-treatment geometric mean counts—praziquantel 96·9% (n = 96 at six months, 51 at two years); the ‘combination’ 93·9% (n = 97 at six months, 48 at two years); and metrifonate 90·3% (n = 92 at six months, 49 at two years). The differences in percentage reduction were not significant (p>0·1). However, a significantly greater reduction in egg ouput was produced by praziquantel (81·7%) and the ‘combination’ (82·5%) than by metrifonate (54·2%), on comparing pre- and post-treatment arithmetic mean counts (p<0·01).A significantly smaller percentage of subjects were excreting ≥125 ova/10 ml urine two years after treatment with praziquantel (10·3%), compared to treatment with the ‘combination’ (25·7%) and metrifonate (35·8%) (p<0·01). The cure rate was significantly higher in the praziquantel group (47·4%) compared to the ‘combination’ (24·7%) and metrifonate (17·4%) groups, for the six to 24-month follow-up period (p<0·001).The pattern and level of transmission had contributed to the long-term efficacy recorded in this study.     

In vitro demonstration of pyrimethamine resistance of “wild” Plasmodium falciparum in the Gambia

The in vitro response of wild¹ Gambian Plasmodium falciparum to pyrimethamine is described. Parasites were grown in 100 μl cultures through schizogony. The number of rings present after 48 hours in drug-treated cultures was expressed as a percentage of the controls. Neither a medium and drug change after 24 hours nor different starting parasitaemias were found to affect the outcome of the assay, although a medium and drug change did increase the multiplication rate. 60 randomly taken pure P. falciparum infections were studied. 57 were sensitive. The ID50 and ID90 of drug-sensitive infections were 1·7 × 10^?9M and 4·5 × 10^?9M pyrimethamine respectively. Three infections were resistant (5%) with individual ID50 values of > 10^?6M, 3 and 4 × 10^?9M and ID90 values of > 10^?6M, 8 and 9 × 10^?7M.     

Characteristics and Clinical Implications of Carbapenemase-Producing Klebsiella pneumoniae Colonization and Infection,Italy

Klebsiella pneumoniae carbapenemase–producing K. pneumoniae (KPC-Kp) has been endemic in Italy since 2013. In a multicenter cohort study, we investigated various aspects of KPC-Kp among patients, including 15-day mortality rates and delays in adequate therapy. Most (77%) KPC-Kp strains were sequence type (ST) ST512 or ST307. During 2017, KPC-Kp prevalence was 3.26 cases/1,000 hospitalized patients. Cumulative incidence of KPC-Kp acquired >48 hours after hospital admission was 0.68% but varied widely between centers. Among patients with mild infections and noninfected colonized patients, 15-day mortality rates were comparable, but rates were much higher among patients with severe infections. Delays of >4 days in receiving adequate therapy more frequently occurred among patients with mild infections than those with severe infections, and delays were less common for patients with known previous KPC-Kp colonization. Italy urgently needs a concerted surveillance system to control the spread of KPC-Kp.     

REVISION OF HYPO-OSMOTIC SWELLING (HOS) TEST WITH A PROPOSITION OF CLASSIFIED GRADING SYSTEM: iTS COMPARISONS WITH FOUR DIFFERENT TYPES OF HUMAN SPERM SEPARATION TECHNIQUE

In this study, we arbitrarily classified the morphological changes of sperm under hypo-osmotic condition and compared the results with four different sperm separation techniques. The morphology of classification ranged from a good swelling (SG 3 > SG 2 > SG 1), to non-swelling but reactive (SG 0-R), and completely non-swelling (SG 0). Thirty fresh semen from patients were divided into 4 groups and each processed by washing, swim up, 2-layer column and real time micro-separation system. The prevalent patterns of the swollen sperm in sequence after treatment was SG 0 > SG 1 > SG 3 > SG2 > SG 0-R in fresh semen, and the proportion of SG 0 was almost half of the total % HOS test results. However, SG 3 became the most common swollen form with a significant increase in number with any method of sperm preparation after treatment. The real time technique yielded the highest % rate of SG 3 type of swollen spermatozoa and was the richest in concentration (53±3.9%, P < 0.05) as compared with that of swim up (26±4.6%), 2-layer (20±4.4%), sperm washing (23±3.9%), and fresh semen (17± 2.8%), respectively. By contrast, 2-layer collected more number of SG0-R (5.3±1.2%, P < 0.05) pattern of spermatozoa when compared to real time and swim up. A positive correlation (r = 0.81, P < 0.002) was shown between the % total HOS spermatozoa and total motility of fresh semen but not with morphology. Collectively, an abnormally functional sperm may exist in almost half of a total sperm count from men. It would appear that a better potential fertilization capacity may reside in the more swollen sperm from HOS test than the less swollen sperm and that may be more related with the motility rather than the morphology. The HOS classification and grading system appears valuable in further evaluating sperm quality.