Electrophoretic keys to identify members of the Anopheles punctulatus complex of vector mosquitoes in Papua New Guinea

Electrophoretic keys are given for the six species of the Anopheles punctulatus complex (Diptera: Culicidae) known from Papua New Guinea plus An.farauti No. 2 and No. 3 from Australia. The categories 'faster', 'standard' and 'slower' are used in keys to relate allozyme band migration following cellulose acetate electrophoresis to the standard pattern. Alternative keys are given depending on the availability of different species for use as standards.

Allozyme analysis reveals six species within the Anopheles punctulatus complex of mosquitoes in Papua New Guinea

Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within the Anopheles punctulatus complex of mosquitoes, by means of cellulose acetate allozyme electrophoresis. An.punctulatus Dönitz sensu stricto was collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari; An.koliensis Owen from eight villages in the Madang area, from Popondetta and Brown River near Karema; and An.farauti No. 1 from ten coastal areas including Madang, Lorengau, Popondetta, Port Moresby, Rabaul and Wewak. Three newly recognized species, reported here for the first time, are designated as An.farauti No. 4 from Gonoa and Hudini, Madang area; An.farauti No. 5 from Ketarabo near Goroka; and An.farauti No. 6 from Hiwanda near Tari. Three other known members of the complex, An.clowi Rozeboom & Knight, An.farauti No. 2 (Bryan, 1973) and An.farauti No. 3 (Mahon & Meithke, 1982) were not detected in Papua New Guinea. Problems arising with morphological characters for the identification of species in this group are discussed.

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 4. Facilitation, limitation, proportionality and their epidemiological significance

Quantitative understanding of the transmission dynamics of lymphatic filarial parasites is essential for the rational planning of control strategies. One of the most important determinants of transmission dynamics is the relationship between parasite yield, the success rate of ingested microfilariae (mf) becoming infective larvae in a mosquito vector, and mf density in the source of the human blood meal. Three types of relationship have been recognized in human filaria/mosquito couples--limitation, facilitation and proportionality; facilitation has hitherto been observed only in the couple Wuchereria bancrofti/Anopheles gambiae in Burkina Faso, in experimental studies on a high density mf carrier. The present paper demonstrates facilitation in W. bancrofti/An. gambiae and W. bancrofti/An. arabiensis in lower mf density carriers in The Gambia and Tanzania, and in W. bancrofti/An. funestus in Tanzania. Facilitation was not found in An. melas in The Gambia nor in An. merus in Tanzania. Analysis of published data shows limitation at low level mf densities in W. bancrofti/Culex quinquefasciatus in Sri Lanka, and in the same couple in India. Limitation also occurs in Brugia malayi/Aedes togoi in experimental cats; proportionality occurs in B. malayi/Mansonia bonneae in Malaysia. The epidemiological significance of these host/parasite relationships is discussed, and supporting evidence for its validity is presented from the published results of large-scale control programmes.

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 3. Uptake and damage to ingested microfilariae by Anopheles gambiae, An. arabiensis, An. merus and An. funestus in east Africa

Laboratory observations were made on the uptake of microfilariae (mf) of Wuchereria bancrofti by Anopheles gambiae, An. arabiensis, An. merus and An. funestus. Over host mf densities ranging from 450/ml to 1735 mf/ml neither the percentage of mosquitoes ingesting mf nor the mean number of mf per mosquito was correlated to host mf density. All mosquito species damaged mf during ingestion but the proportion harmed was independent of host mf density. The mean proportion damaged was 0.67 in An. gambiae, 0.51 in An. merus, 0.47 in An. Arabiensis and 0.26 in An. funestus. A comparison of the mean number of undamaged mf ingested and the number of larvae in the thoracic muscles revealed that not all undamaged mf were able to reach the thoracic muscles.

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 1. Uptake of microfilariae

Ingestion of Wuchereria bancrofti microfilariae (mf) from humans by 639 Anopheles gambiae, 557 An. arabiensis, 117 An. melas and 9 An. funestus was investigated. The mf densities in blood fell into 3 groups; 0-32mf/ml, 107-122 mf/ml and 421-1140 mf/ml. In An. gambiae and An. arabiensis percentage of mosquitoes ingesting mf was strongly associated with mf density in host blood; in An. melas the association was much weaker. Mean number of mf ingested per mosquito was also strongly correlated to mf density in An. gambiae and An. arabiensis but not in An. melas. At low mf densities both An. gambiae and An. arabiensis concentrated mf, with concentration decreasing as density increased. From regression analysis, observed and expected uptake of mf would be equal at 622.9 mf/ml in An. gambiae and 391.6 mf/ml in An. arabiensis.

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 2. Damage to ingested microfilariae by mosquito foregut armatures and development of filarial larvae in mosquitoes

Microfilariae (mf) of Wuchereria bancrofti from the midgut of 639 Anopheles gambiae, 557 An. arabiensis, 117 An. melas and 9 An. funestus were examined immediately after the mosquitoes had fed on carriers with different densities of mf. The percentages of mf damaged during ingestion were 57.1-60.0 in An. gambiae, 33.3-50.6 in An. arabiensis and 38.7-55.7 in An. melas. In each species the percentage of mf damaged was independent of mf density in the human host. A further 3657 An. gambiae, 2875 An. arabiensis, 347 An. melas and 32 An. funestus were examined 7 d or more after feeding on mf carriers. In An. gambiae and An. arabiensis, mean numbers of larvae per mosquito were strongly correlated to mf blood density, with similar regression slopes to those obtained from the regression of mf blood density on mean uptake of mf/mosquito. The ratio of mean numbers of larvae per mosquito to mean numbers of intact mf ingested per mosquito increased as the density of mf in the human host increased in An. gambiae and An. arabiensis, but decreased in An. melas as host mf density increased.

A mark-recapture experiment with the filariasis vector Anopheles punctulatus in Papua New Guinea

A capture-recapture experiment with the filariasis vector Anopheles punctulatus from Papua New Guinea (PNG) is described. Eight hundred and ninety-seven engorged females collected indoor resting or in landing catches were released, and 82 were subsequently recaptured. Infection rates were higher in recaptured mosquitoes than in unmarked ones. Recapture rates declined exponentially with distance from the release site, but an infected female was recaptured 1.8 km from the release site. The estimated oviposition interval of 2.90 days was shorter than that obtained from the same species elsewhere in PNG, but daily survival rates were similar. Infection with Wuchereria bancrofti did not appear to affect the survival of the mosquito. Collections adequately sampled the resting population from inside a room of an experimental house.

Adult behaviour of members of the Anopheles gambiae complex in the Gambia with special reference to An. melas and its chromosomal variants

Polytene chromosome studies on the member species of the Anopheles gambiae complex in The Gambia and surrounding areas in Senegal led to comparative observations on bionomics of sympatric populations of An. melas and An. gambiae. Moreover, inversion polymorphisms have been analyzed in An. melas and their possible relationships with behavioural variations in endophily and anthropophily have been considered. An. melas shows a remarkably short dispersal from typical larval breeding places associated with mangrove swamps and it is definitely more zoophilic and exophilic than An. gambiae. Only a very small fraction of An. melas biting outdoor on animals rests indoors and consequently the human blood index is largely overestimated if based on the examination of house samples alone. Differences in the frequencies of 2Rn inversion karyotypes of An. melas were observed between parallel samples obtained from animal shelters and houses, from night catches on man outdoor and from night catches on main indoor and on animal outdoor. Further differences were shown by blood meal identification between human and animal fed subsamples from the same house resting samples. Non-uniform feeding and/or resting behaviour between carriers of alternative 2Rn inversion karyotypes is postulated to explain these data.

The Larval Salivary-Gland Polytene Chromosomes of Anopheles (Cellia) Annulipes Sl Walker (Diptera, Culicidae)

A photomap of the larval salivary gland chromosomes of An. annulipes from colony material arbitrarily chosen as standard for this taxon is presented. Also illustrated are seven types of X chromosomes which have been revealed in this multi-species taxon.

Vectors of Wuchereria bancrofti in the Sepik Provinces of Papua New Guinea

The vectors of Wuchereria bancrofti were investigated in two areas of the Sepik Provinces of Papua New Guinea. At the village of Yauatong, indoor-resting Anopheles punctulatus had an infection rate of 47.3% and an infective rate of 3.4%. No infections occurred in 382 Culex annulirostris obtained in night-landing catches. At the village of Yankok only An. koliensis contained infective larvae but An. punctulatus and Cx quinquefasciatus were infected. Probit values of the cumulative percentages of filariae-positive mosquitoes plotted against the logarithm of the corresponding filaria count are illustrated.

Nucleolar hypertrophy as an indicator of transcription in cells infected with second generation meronts of Eimeria tenella

Changes in nuclei and nucleoli of cells of chicken cecum infected with Eimeria tenella were studied in living cells by interference microscopy and in fixed and stained tissues using light level microscopy. As soon as merozoites began to transform into second generation meronts, there was an increase in the size of both the nucleus and the nucleolus of the host cell. The dry weight of the nucleus increased somewhat, but there was a greater increase and a correlation of the dry mass of the nucleolus with the size of the parasite as measured by interference microscopy. In fixed and stained tissues, there was a correlation between the area of the nucleolus and the area of the parasite. Removal of nucleic acids with DNase and/or RNase showed high concentrations of both in the nucleoli and a residue of protein. The increased nucleolar size indicates a high level of transcription in infected cells and allows the conclusion that the parasite somehow induces transcription to occur. Since transcription is a highly specific process, the high degree of host and site specificity shown by nearly all coccidia is consistent with a hypothesis that the coccidia share a portion of the host genome.

First impressions, ingratiation, and the learning disabled child

Two experiments were conducted concerning college students' immediate impressions of male learning disabled and nondisabled children. In both experiments, one half of the stimulus children within each group had been instructed to ingratiate an interviewer; the remaining youngsters had been instructed to act naturally. Interviews centered around the children's descriptions of their favorite television programs and movies. College students in the experiments viewed either 10- or 25-seconds of videotape of the interactions of each child. After each 10-or 25-second sequence the college students rated the child as to his degree of social adaptability and social hostility. Experiment I demonstrated that while LD children were judged more negatively under the “act naturally” instructions. thesechildren were judged as positively as nondisabled children when prompted to ingratiate. In Experiment II, judges based their ratings solely on the nonverbal behaviors of the target children. Again, a group by instruction interaction was found and was similar in nature to that found in Experiment I.

Anopheles gambiae and A. melas at Brefet, The Gambia, and their role in malaria transmission

Anopheles melas and A. gambiae were studied at the village of Brefet, The Gambia. The population density of A. gambiae varied according to the rainfall. However, this was not so with A. melas, the highest densities of which occurred after the cessation of the rains. The sporozoite rate averaged 3.5% in A. gambiae but only 0.35% in A. melas. Possible causes of these differences are discussed.

The immotile cilia syndrome. Mice versus man

When homozygous the recessive, pleiotropic, mutation hpy (hydrocephalic-polydactyl) produces post-natal hydrocephalus, complete sterility in males, and reduced reproductive performance in females. Because the fertility problems and the development of hydrocephalus could arise as consequences of defective flagella and ciliary axonemes, this mutant type might serve as a useful animal model for the immotile cilia syndrome. Ultrastructural defects seen in axonemes of flagella, and of cilia from the trachea, oviduct, and ependyma included: a deficiency of inner dynein arms (the most frequent defect); an absence of one or both central-pair tubules; extra central tubules; a displacement of one outer doublet and/or the central-pair tubules. Some axonemes showed more than one of these defects. The frequency of dynein-deficient axonemes in all three tissues was similar (about 35%) and fell within the range reported for human patients with the immotile cilia syndrome. On this basis, this mutant type might be considered as a useful animal model for such studies. There were no indications of situs inversus, nor was there a marked increase in respiratory problems. So hpy/hpy mice do not exhibit all of the clinical symptoms characteristic of the human condition.

Abnormal cilia in a male-sterile mutant mouse

In mice homozygous for the mutation hydrocephalic-polydactyl (hpy) ciliary axonemes from tracheal, oviducal, and ependymal lining cells showed a variety of abnormalities. Defects included: a deficiency of inner dynein arms, extra central tubules, a displacement of one outer doublet and/or the central tubules, and double axonemes. More than one kind of defect was seen in some axonemes. None of the types of defects observed in mutants were encountered in equivalent samples from non-mutant littermates. Except for the most common defect, the deficiency in dynein arms, which occurred to about the same extent (approximately 34%) in all three tissues, there were marked variations in frequency among the tissue types with respect to the other defects. In general, defects such as central tubule anomalies, displaced tubules, and double axonemes occurred with the highest frequencies in axonemes from tracheal epithelial cells and with the lowest frequencies in samples of oviducal epithelium. Fused cilia were seen only in ependymal cell samples. Some of the defects encountered were common to sperm flagella axonemes while others appeared restricted to somatic tissues, suggesting, perhaps, each tissue type may exert its own modulating influence on the expression of the mutant gene.

Leishmaniasis in The Gambia. 2. A study of possible vectors and animal reservoirs, with the first report of a case of canine leishmaniasis in The Gambia

Following the detection of two cases of leishmaniasis in The Gambia, the possible vectors and animal reservoirs were studied. A total of 5, 158 phlebotomine sandflies, in 20 species and subspecies were captured, including 98 males and 61 females of Phlebotomus duboscqi. This species is a vector of cutaneous leishmaniasis in Senegal and must be suspected as a vector in The Gambia; it was captured close to the dwellings of both patients and from rodent burrows, including those of Mastomys erythroleucus, a known reservoir of cutaneous leishmaniasis in Senegal. We report the first finding in The Gambia of visceral leishmaniasis in a dog captured near the house of the patient with visceral leishmaniasis. This strongly suggests that dogs could be a reservoir of this infection in this area. The vector was not determined.

Spermatogenesis revisited. V. Spermiogenesis in mice homozygous for two different male-sterile mutations (ps and hpy)

In male mice homozygous for both ps and hpy, two recessive, pleiotrophic, mutations, gametogenesis is normal through meiosis but no functional spermatozoa are produced. Spermiogenesis is abnormal from the Golgi phase on. The types of abnormalities seen during the early and mid-stages of spermiogenesis are characteristic of those associated with the presence of the ps mutation whereas those associated with the hpy mutation appear during the later stages of spermatid development. While centriolar ultrastructure was normal, axonemal structures were only rarely encountered and no late spermatids with recognizable flagella were seen. Some late spermatids showed head abnormalities of the type characteristic of the ps mutation while others were recognizable as being of the hpy type. A released "gamete" usually consisted of a distorted nucleus and associated acrosome enclosed in a tightly fitting plasma membrane. No spermatids exhibiting a novel phenotype were encountered. The findings support the view that, despite their simultaneous presence in the double homozygote, each mutation acts autonomously. These studies also allow a similar inference to be made with respect to the extent of the interrelationship of the other major sub-processes of spermiogenesis.