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Infectious DNA from adeno-associated satellite virus (ASV) has been isolated from cells coinfected with a temperature-sensitive mutant of herpes simplex virus (HSV) type 1 in the absence of contaminating HSV DNA. This satellite virus DNA does not appear to differ in its physical, chemical and biological properties from DNA isolated directly from virions or from cells co-infected with adenovirus. The DNA is double-stranded with a buoyant density of 1.718 gm/cm(3). It sediments at 16S in both neutral and alkaline sucrose gradients. Single-stranded DNA from alkaline sucrose gradients has a modal length of 1.5 mum and demonstrates evidence of internal redundancies in the electron microscope.

Two virus strains isolated from stools of poliomyelitis patients were apparently a mixture of a type 2 strain of poliomyelitis virus, and of a strain of the Columbia SK group of viruses. Both components of the E.S. strain could be separated by neutralization of second passage cynomolgus monkey cord with either Lansing or Columbia SK hyperimmune serum. A similar technique with the 19th monkey passage of the A.K. strain failed to separate the components of this strain, which is suggested to be due to interference. Under experimental conditions, the murine A.K. strain was shown to interfere with the simian A.K. strain. Similarly, the original Columbia SK virus interfered with the Aycock strain of type 2 poliomyelitis virus. No interference was observed between the murine A.K. strain and types 1 and 3 poliomyelitis virus.

The Hb A2 level in erythrocytes was determined in 42 malaria patients who did not have β-thalassaemia or Hb E. 15 had P. vivax, 26 had P. falciparum, and 1 had a mixed infection. The Hb A2 values ranged from 1·9 to 5·1% with a mean of 3·32% (S.D. 0·69%); in 109 normal healthy persons without signs of β-thalassaemia, the range was 1·6 to 3·9% with a mean of 3·04% (S.D. 0·45%); and in 41 β-thalasseamia trait carriers the Hb A2 values ranged from 4·4 to 8·1% with a mean of 6·24% (S.D. 0·74%). The mean in the group of malaria patients is significantly higher (p

When cells are mixedly infected with two heat-defective ( hd ) poliovirus mutants at temperatures above those that are optimal for growth of these mutants, the virus yield is 4–14 times the sum of the yields of each mutant when grown separately under identical conditions (“leak” yields). The mixed infection yields are only one thousandth of the yield of wild type ( hd+ ) under these conditions. The leak and mixed infection yields are 90–99% mutant rather than hd+ , but only one of the mutants was detected in the mixed infection yields. Any rescue of the hd mutants by hd+ was too small to be detected.

A study was carried out on mixed infections with P. vinckei and P. berghei in white mice. Daily parasite counts of invaded mature and young red cells in animals inoculated simultaneously with both plasmodia, compared with their numbers and distribution in single plasmodial species control groups, gave clear results, showing the predominance of P. vinckei , in the mixed, concomitant infection and its antagonistic effect on P. berghei development. A strong suppressive effect on P. berghei gametocyte production in animals developing mixed P. vinckei and P. berghei infections was observed. This effect led to the disappearance of P. berghei gametocytes from the peripheral blood in animals with concomitant infections on the sixth day of their overt parasitaemia.

1. There are cases in which epithelial cell inclusions may alone be present in the conjunctival smears. In such cases no other pathogenic organisms, such as the Koch-Weeks bacillus or the pneurnococcus, can be demonstrated in smears or cultures. 2. The conjunctiva can become simultaneously infected with the inclusion bodies and Koch-Weeks bacilli or other organisms. 3. In cases of acute or subacute conjunctival inflammations due to mixed infections the clinical features of each infection may be present. The course of the inflammation is, however, more prolonged. 4. Within recent years, the Koch-Weeks bacillus has only seldom been found in our routine examinations. 5. The epidemic studied was of a severe type. 6. Clinically it is practically impossible to distinguish pneurnococcal conjunctivitis from the Koch-Weeks conjunctivitis. Bacteriological examination of smears and cultures is the only means by which the etiological diagnosis can be definitely established. 7. Conjunctivæ of certain species of monkeys are susceptible to the von Prowazek inclusion bodies, but not to the hemoglobinophilic bacilli isolated from cases of epidemic conjunctivitis. 8. The injection of conjunctival scrapings containing the von Prowazek cell inclusions into the testicles of rabbits produces no cell inclusions in the latter, while the injection of a pure culture of the hemoglofcinophilic bacilli causes an acute inflammation accompanied by numerous clumps of the organisms, simulating the von Prowazek bodies at certain stages of their evolution. 9. There exists an apparent morphological similarity between the degenerated forms of this variety of the hemoglobinophilic bacilli and the cell inclusions, both in cultures and in experimental orchitis in the rabbit. But, as a rule, the elementary bodies of the latter are much smaller and more sharply defined than the smallest granules of the former, while the initial bodies are bigger, more intensely stainable, and less definite in their contour than the hemoglobinophilic bacilli found in the infected conjunctivæ.

In a series of experiments varying in the order of, and in the intervals between infections, albino mice were concomitantly exposed to S. mansoni and T. cruzi . A most striking finding was the pronounced enhancement of parasitaemia due to T. cruzi in mixed infections, present in all the series, whose interval between exposures ranged from 4 to 66 days. In some groups of animals the peripheral blood remained positive for T. cruzi long after controls had been found to be negative. When Chagas's infection preceded exposure to cercariae worm recovery was also affected. Worm recovery was always significantly lower in mixed infections, in series where the interval between exposures ranged from 5 to 16 days. At longer intervals (63 days) the number of flukes recovered at autopsy was significantly higher than in the control mice.

1. 1. Six cases of ulcerative granuloma treated with varying combinations of antimony salts with sulphanilamide derivatives are described. 2. 2. Disadvantages and limitations of fuadin and sulphanilamide, used alone, are indicated. 3. 3. Favourable results obtained by combining fuadin injections with M. & B. 693 orally are recorded. 4. 4. A case of mixed infection (ulcerative granuloma and lymphopathia venereum) amenable to fuadin combined with M. & B. 693 is included in the series.

Although sera derived from patients at the time of acute, active infection were found to be capable of destroying hemolytic streptococci under aerobic conditions, the organisms retained viability when the tests were performed in the environment of anaerobiosis afforded by a vaseline seal or an anaerobic jar. Within the limitations of the experimental procedures which were employed, the aerobic or anaerobic effect was found to be a reversible reaction. Heating sera at 60°C. for 1 hour inactivated the streptococcidal element in most instances, but not in every case; heating at 56°C. for 1 hour impaired the killing power of half of the specimens which were tested. Sera retained the capacity to destroy hemolytic streptococci when kept in the ice box for 3 weeks; a slight diminution in killing power was noted after 4 weeks. By the methods which were employed, the streptococcidal property of sera could not be correlated with either true antibacterial agglutination or with pseudo-agglutination. The significance of the findings as a basis for analyzing the mechanism of the streptococcidal phenomenon is discussed.

1. The vital importance of the cellular defense forces in the resistance of the monkey to combined streptococcus and influenza virus infections has been demonstrated. 2. Some of the conditions prejudicial to the maintenance of an optimum cellular reserve in the infected animal have been revealed; viz., undernutrition, physical cold, intratracheal route of infection. 3. The potential threat exerted by latent foci of streptococci, and the importance, in relation to the combined infection with virus, of cellular and humoral immunity, together or separately, have been demonstrated. The essential rôle of optimum nutrition (notably as concerns the vitamin B complex, and folic acid specifically) in the prevention of disastrous illness from these infectious agents, individually or in combination, would seem to have been proven. 4. Signs of glomerular nephritis appeared in a significant number of monkeys receiving Streptococcus hemolyticus and influenza virus in sequence, followed by reinoculation or spontaneous reappearance of the streptococci. 5. Reinoculation of Streptococcus hemolyticus, group C, resulted in a prompt "booster" increase in the opsonic index. Virus instillation was followed by just as sudden a depression in this index. 6. Reinoculation failed to evoke either the granulocytosis or the leucopenia in monkeys which are characteristic effects of the streptococcus and the virus respectively when these agents are introduced for the first time by way of the nasal mucous membrane. 7. Simultaneous intranasal inoculation of influenza virus, type A, and Streptococcus hemolyticus, group C, in nutritionally normal Macaca mulatta failed to produce obvious signs of disease. In most of the animals, however, a streptococcus-induced leucocytosis followed by a delayed virus-induced granulopenia developed. 8. Inoculation of influenza virus followed in 4 to 17 days by streptococci produced obvious signs of disease in five of eleven animals which had become leucopenic as result of the action of the virus, and fatal streptococcal septicemia in two monkeys. 9. The development of signs of infection in previously healthy monkeys exposed to virus followed by streptococci confirms both the clinical and laboratory experience of other observers, that virus infection may predispose to secondary bacterial invasion, and, that at times, under unfavorable circumstances, the infection may become overwhelming. Although the complete mechanism of resistance is as yet not wholly clear, the depressant or inhibitory effect of the virus on both its cellular and humoral elements has been established.

Mutants of two strains of Newcastle disease virus which differ from each other in three characteristics (plaque type, heat stability, and serotype) were used to mixedly infect chick embryo cells at high multiplicities. After plating out mixed yields, 90% of the plaques were found to contain only one parental virus type but 10% contained both parental types and experiments indicate that these mixed plaques were initiated by heterozygous particles which were probably diploid. A high proportion of the particles from mixed infections showed evidence of phenotypic mixing both in respect to serotype and thermal stability. When the fluid from mixed infections was used to singly infect cells, there were large numbers of phenotypically mixed particles in the yield. The amount of phenotypic mixing could be accounted for by the number of heterozygotes in the inoculum. Mixed infections at low multiplicities yielded five to ten times as much phenotypically mixed virus as could be accounted for by the number of cells expected to be mixedly infected by two plaque-forming particles. The results suggest that nonplaque-forming particles may contribute to the phenotype of new virus induced by infection with plaque-forming virus.

The data presented agree with and supplement the results reported on the basis of the clinical examination in 1957. Tinea capitis of microsporic and trichophytic origin is common in the Congo and Ruanda Burundi and is caused mainly by seven species of dermatophytes:—M. langeroni, M. rivalieri, T. ferrugineum, T. kuryangei, T. soudanense, T. violaceum and T. yaoundei. The most important species are M. langeroni which was isolated 195 times (41·8%) and T. violaceum which was isolated 152 times (32·3%). Species of Microsporum with T. ferrugineum cause 55·2% and species of Trichophyton 44·8% of tinea capitis infections. Of the 50 culture negative cases, 33 were positive by microscopic and/or Wood's light examination, thus clinical diagnosis was correct in at least 97% of the cases. Thirty-seven cases of mixed infection are reported and discussed. The frequency of dermatophyte infection in Kwashiorkor children is shown to be as high as 93%.

Double infection of the allantoic sac with Melbourne and WSN viruses induced the formation of a combination virus, which had some of the antigenic properties of both parents and which maintained itself through serial passage in the chorioallantoic sac. In the course of prolonged passage in the egg, three varieties of combination virus were found. The first (X1) occurred in ten passages and was characterized as follows: X1 was produced in and could be successfully passed from those chick embryos that had received very large inocula of virus. The X1 hemagglutinin was efficiently inhibited by both M and W antisera. Each passage fluid, containing X1 as the predominant strain, also contained large amounts of the parent forms M and W. It is very likely that X1 reverted to parent types of virus at a high rate. The second variety (X2) arose from the passage series of X1 and was carried for approximately 20 passages without definite alteration in its character. It differed from X1 in that it had the ability to appear as the predominant form occasionally in embryos that had received a limiting infective dilution of virus. Because of this, it seems probable that X2 reverted to parent types at a slower rate than X1. Like X1, this virus was never obtained in pure form and suspensions in which it predominated contained large amounts of M and W, especially the former. Good evidence was obtained that X2 reverted to M and W virus while multiplying in the chorioallantoic sac. X3 was derived from passage of X2 virus after 32 transfers and can be characterized in several ways: (a) X3 yielded the only X3 fluids on passage in eggs. This was in striking contrast to X2 which could not be passed without giving rise to some fluids in which M and W predominated, (b) The X3 hemagglutinin was weakly inhibited by all but the highest concentrations of M serum, but was strongly inhibited by W serum. X2 was readily inhibited by relatively small amounts of both sera. (c) X3 virus, after several passages at limiting dilutions, was neutralized to a highly significant degree by specific M and W sera. This is not necessarily an essential difference from the behavior of X2 since technical difficulties (large amounts of M and W in X2 fluids) may have prevented the demonstration of equally striking double neutralization of this virus, (d) After five limiting dilution passages, the X3 virus retained the characteristics listed under (a) to (c). It is felt that the foregoing facts justify the conclusion that X3 is a stable virus which combines some of the specific antigens of two parent types.

1. (1) Wild animals shot in tsetse areas of Shinyanga (Glossina swynnertoni and G. pallidipes) and Ukerewe peninsula (C. swynnertoni) have been examined for trypanosomes. 2. (2) The results of examining a number of individuals from twenty-two animals are given in Table I. A total of 22·2 per cent. of all the animals examined showed trypanosomes in their bloods; of these 0·7 per cent. showed T. brucei, 20 per cent. T. congolense and 3·7 per cent. T. vivax. A few animals showed mixed infections. 3. (3) Of forty-five impala examined 20 per cent. were infected; of twenty-one giraffe examined 47·6 per cent. showed infection, and of nineteen wart-hog 15·8 per cent. were infected. 4. (4) Tables II and III give figures that suggest that the young animals show a higher per cent. infection than the adults, and that a higher per cent. infection is found during the rains. These figures, however, are insufficient for statistical treatment, and therefore must be taken with reserve.

Splenomegaly in P. berghei yoelii infection occurred earlier but lasted a shorter time than in P. chabaudi . In mixed simultaneous infections the enlargement occurred as early as in the Pby infections done but lasted as long as in the Pch infections. The magnitude of the whole course of enlargement was greatest in the case of mixed infections. Data were also obtained on IgG and IgM levels and IgG fluorescent titres for malaria during the course of these rodent malaria infections. It is pointed out that the rodent model has certain deficiencies if used to try to understand splenic response to plasmodial challenge in man. A similar experimental design in primate malaria would yield more valuable information.

(1) An acute gonorrhœal urethritis may be the starting point for a grave general septicæmia with all its possible complications. (2) These infections may be mixed or secondary, due to the entrance into the circulation of organisms other than the gonococcus, or they may be purely gonococcal in nature. (3) Endocarditis is an occasional complication of gonorrhœa. (4) This endocarditis may be transient, disappearing with but few apparent results, or it may leave the patient with a chronic valvular lesion, or it may pursue a rapidly fatal course with the symptoms of acute ulcerative endocarditis. (5) The endocarditis associated with gonorrhœa is commonly due to the direct action of the gonococcus, hut may be the result of a secondary or mixed infection. (6) Pericarditis may also occur as a complication of gonorrhœa, but it is less frequent than endocarditis. It may, as in the case of the latter, be the result either of a pure gonococcal or of a mixed infection. (7) Grave myocardial changes, necroses, purulent infiltration, embolic abscesses are common in the severe gonococcal septicæmias. (8) In instances of gonococcal septicæmia the diagnosis may, in some cases, be made during life by cultures taken from the circulating blood according to proper methods.

The occurrence in the same locality and at the same time of the viruses of both vesicular stomatitis and foot-and-mouth disease is a possibility disquieting to those who are responsible for the control of vesicular diseases of cattle and swine. This is particularly liable to occur in countries in which vesicular stomatitis is enzootic and in which relatively little attention is paid to this condition. In these circumstances it is feared that the existence of foot-and-mouth disease may be masked or obscured by the milder vesicular stomatitis until such time as it has become widespread in the animal population. The possibility of concurrent infection with the two viruses has been suggested (Galloway & Elford, 1935), but the problem has not been studied in cattle before, and evidence cannot, therefore, be adduced on the probable behaviour of a mixture of the viruses during passage by natural transmission in a population of susceptible cattle. Our present knowledge, supported by the evidence to be given here, suggests that a mixed infection is possible if the requisite field conditions exist. It is less probable that a mixed infection could continue to exist during the spread of the disease without the stronger component becoming dominant, resulting in the extinction of the weaker virus. The occurrence of mixtures consisting predominantly of the virus of vesicular stomatitis would be favoured if the susceptibility of the cattle population to foot-and-mouth disease were modified by vaccination, especially if the immunity to foot-and-mouth disease were waning and the virus of foot-and-mouth disease were gaining a hold among the animals. The possibility of such a set of circumstances emphasizes the need for information on the reliability of methods for the detection of the virus of foot-and-mouth disease in the hypothetical early stage of the mixed outbreak when the virus of vesicular stomatitis should be present in great excess. The differentiation of the viruses of vesicular stomatitis and foot-and-mouth disease has been discussed by Galloway (1936), and a method has been described for using the complement-fixation test (Brooksby, 1948). Some of the methods discussed are of uncertain value when the detection of a small amount of one virus in a mixture is required. In the resolution of mixtures, Galloway & Elford (1935) took advantage of the pathogenicity of the virus of vesicular stomatitis for the chick embryo in order readily to detect small amounts of this virus. More important, however, from the disease control aspect, is the possibility of detection of a small amount of the virus of foot-and-mouth disease which causes the more dangerous disease. For the detection of small amounts of the virus of foot-and mouth disease (10 M.I.D. or less), Galloway & Elford were successful in applying a filtration method, in which 'Gradocol' membranes of selected porosity were used to retain the larger virus and allow the virus of foot-and-mouth disease to pass.

A study was made of the consequences of the introduction, by superinfection or mutation, of a marked type of Rous sarcoma virus (RSV) into chicken embryonic cells already infected with RSV. Characters controlling cell morphology (Temin, 1960) were used as markers. After superinfection, cells can release virus of the original type only, of the superinfecting type only, or of both the original and superinfecting types. Over ten generations after superinfection, single cells can release two types of virus. Cells which release both viruses can have the morphology of either type; the virus that controls cell type can be either the original or the superinfecting virus. It was found that the proportion of mutant virus and the proportion of mutant cells in clonal populations of Rous sarcoma cells was similar.

biology. Indeed, studies of this phenomenon from a therapeutic point of view contributed to the development of antibiotics. More recently, direct bacterial interference, rather than the use of an active microbial product, has been employed in situations in which repeated therapy with antibiotics has been ineffective. The most notable use of interference has been with staphylococci; an avirulent strain has been inoculated to terminate epidemics of staphylococcal infection in newborn infants [1, 2] and to stop repeated infections in individuals [3, 4] or to halt the spread of intrafamilial infections [5, 6]. Comparable studies have not been conducted in human pyelonephritis, but the question frequently arises whether mixed infections exist when several bacteria are isolated from the urine or appear sequentially with or without therapy. If mixed infections do exist, the role of bacterial interference in maintaining relationships between different bacteria may need study. The availability of a model of experimental pyelonephritis in the rat has permitted study of bacterial interference in renal disease. Streptococ

The present studies were designed to characterize the response of sheep infected with N. spathiger to challenge infection with the same species.The results showed that: (1) the level of worm counts attained on secondary infection with the parasite was much reduced compared with the counts recorded following initial infection; (2) the relative fecundities of parasite populations which developed in individual hosts following challenge infection, ranked in magnitude in an order which was similar to that established following initial infection; (3) as fecundity was highly correlated with the number of egg-laying females and the number of males and females was nearly equal in individual specimens, it was concluded that worm burdens were also ranked for individual animals on primary infection and following challenge; and (4) the animals of the control group remained as susceptible as the animals of groups 1 and 3 at the time of their primary infection; consequently, in the absence of previous immunological experience due to infection, there was no apparent change in susceptibility of the animals due to an effect of age during the course of the 17 weeks of the experiment.We are greatly indebted to Dr Michael Tallis, Division of Mathematical Statistics, C.S.I.R.O., for advice and assistance with the statistical analyses, and to Dr D. F. Stewart for his interest and constructive criticism during the course of these studies. Our thanks are also due to Mr E. Teleki and Misses Helen Giller and Lindy Stothart for their valuable technical assistance.

SummaryA comparison was made of serum-bound carbohydrates of hosts bearing Walker 256 carcinosarcoma contaminated with Salmonella typhimurium and “bacteria-free”tumor hosts. It was found that “contamination”resulted in increased levels of total serum-bound carbohydrates whereas the “bacteria-free”levels were decreased or unaltered. Relating the carbohydrate levels to tumor growth revealed that in the “contaminated”group the carbohydrate levels were elevated prior to the rapid phase of growth while the “bacteria-free”group showed decreased levels during this stage of growth. It was emphasized that caution should be exercised in evaluation of tumor-host data.

1.1. Eight patients having stage III and IV carcinomas of the cervix, which were secondarily infected, were treated with daily doses of 400,000 units penicillin given in eight divided doses for seven days. 2.2. Bacteriologic and leucocytic counts were taken before treatment, after seven days of penicillin treatment, and twenty-one days after the discontinuance of penicillin. 3.3. Those cases with visible cervical lesions were only temporarily benefited. 4.4. Those cases with no visible cervical lesion still showed considerable improvement three weeks after cessation of treatment.

Events occurring during the abortive infection of monkey cells by human adenoviruses have been compared to those occurring during the complete replicative cycle which results from adenovirus and SV40 coinfection of these cells. Previous studies had indicated a block to replication at a posttranscriptional level. This paper describes the examination of two posttranscriptional events: attachment of polyadenylic acid sequences to adenovirus mRNA, and association of this mRNA with polyribosomes. Posttranscriptional addition of poly(A) sequences to mRNA appears to take place normally in the absence of SV40 coinfection. “Late” adenovirus mRNA, though synthesized in the nonpermissive infection, appears to be deficient in its association with polyribosomes. This finding is consistent with the previously described defect in late adenovirus protein synthesis in the unenhanced infection of monkey cells.

BACKGROUND: A significant segment of the world’s population is at risk of contracting malaria infection at any one time. In Ethiopia, sustained control efforts have been made in the past decade to fight malaria. Yet, it remains as the major cause of morbidity, mortality and socioeconomic problems in the country. The intensified control of malaria can further be augmented by analyzing health facility based malaria data. Hence, the aim of this study was to determine the magnitude of malaria infection in Northwest Ethiopia.METHODS: A retrospective record review was conducted in Northwest Ethiopia from February-April 2016. All blood film results reported between January 2013 and December 2015 in the seven health centers were extracted and analyzed.RESULTS: A total of 41,773 patients with chief malaria complaint were screened for malaria in the three years period. The overall prevalence of microscopically confirmed malaria was 28.1%. Males (29.5%) were more affected by malaria than females (26.5%). Malaria was also higher in the age group >15 years (32.6%) followed by 5-15 years (29.3%) and under-five children (20.5%). Plasmodium falciparum, Plasmodium vivax and mixed infectionsaccounted for 58.2%, 35.5% and 6.3%, respectively. The highest prevalence of confirmed malaria cases was observed during spring (35.6%) and summer (25.1%). Higher prevalence of slide positive malaria was recorded in Dima (46.1%), Cherecher (45.3%) andFyel wuha (35.3%) health centers.CONCLUSION: Malaria specific outpatient cases were high in the study area. Both plasmodia species were of public health significance in the area with predominance of Plasmodiumfalciparum.

Cetyltrimethylammonium bromide incorporated in an aromatic mix base is effective in the treatment of primary and secondary pyogenic cutaneous infections. The failure of this preparation to produce allergic reactions suggests a low sensitizing index.