We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

Manuscript in preparation

The body encloses a complex antioxidant defence grid that relies on endogenous enzymatic and non-enzymatic antioxidants. These molecules collectively act against free radicals to resist their damag...

https://www.ajol.info/index.php/bafm/article/download/182149/171529

First line defence antioxidants-superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX): Their fundamental role in the entire antioxidant defence grid

We redescribe the only previously known species of Myrsidea from bulbuls, M. pycnonoti Eichler. Sixteen new species are described; they and their type hosts are: M. phillipsi ex Pycnonotus goiavier goiavier (Scopoli), M. gieferi ex P. goiavier suluensis Mearns, M. kulpai ex P. flavescens Blyth, M. finlaysoni ex P. finlaysoni Strickland, M. kathleenae ex P. cafer (L.), M. warwicki ex Ixos philippinus (J. R. Forster), M. mcclurei ex Microscelis amaurotis (Temminck), M. zeylanici ex P. zeylanicus (Gmelin), M. plumosi ex P. plumosus Blyth, M. eutiloti ex P. eutilotus (Jardine and Selby), M. adamsae ex P. urostictus (Salvadori), M. ochracei ex Criniger ochraceus F. Moore, M. borbonici ex Hypsipetes borbonicus (J. R. Forster), M. johnsoni ex P. atriceps (Temminck), M. palmai ex C. ochraceus, and M. claytoni ex P. eutilotus. A key is provided for the identification of these 17 species.

A new species

Ticks and tick-borne diseases affect animal and human health worldwide and are the cause of significant economic losses. Approximately 10% of the currently known 867 tick species act as vectors of a broad range of pathogens of domestic animals and humans and are also responsible for damage directly due to their feeding behaviour. The most important tick species and the effects they cause are listed. The impact on the global economy is considered to be high and although some estimates are given, there is a lack of reliable data. The impact of ticks and tick-borne diseases on animal production and public health and their control are discussed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/2CCD9EAD34FA5E2FB3CD37DAAFFF7F56/S0031182004005967a.pdf/div-class-title-the-global-importance-of-ticks-div.pdf

The global importance of ticks.

Tick Vector Biology

Helminths and arthropods were collected and quantified from two black rhinoceroses (Diceros bicornis bicornis) and one white rhinoceros (Ceratotherium simum), and ticks from an additional four black and two white rhinoceroses in southern Africa. The helminths of a black rhinoceros from the Republic of South Africa and one from Namibia were quantitatively measured and recorded for each compartment of the alimentary tract. Probstmayria vivipara was the most abundant parasite in each animal. A recently described nematode, Diceronema versterae, was found in the stomach of one animal. Draschia megastoma was present in the descending colon of the same animal, but it was twice the size of similar specimens reported from equids and the typical granulomatous lesions caused by this nematode in horses were not observed. New records of other helminths from rhinoceroses include Parabronema roundi, Kiluluma sp., Kiluluma goodeyi, Kiluluma magna, Khalilia rhinocerotis, Oxyuris karamoja and Anoplocephala gigantea. The stomach bot, Gyrostigma pavesii, was collected from one black and one white rhinoceros. Ticks collected from the black rhinoceroses were Amblyomma hebraeum, Dermacentor rhinocerinus, Rhipicephalus maculatus, Rhipicephalus muehlensi and Haemaphysalis silacea. The two white rhinoceroses were infected with A. hebraeum, D. rhinocerinus, Hyalomma truncatum, Rhipicephalus simus, Rhipicephalus appendiculatus and Rhipicephalus zambeziensis.

Helminths and arthropods of black and white rhinoceroses in southern Africa.

A total of 586 reptiles, belonging to 35 species and five subspecies, were examined in surveys aimed at determining the species spectrum and geographic distribution of ticks that infest them. Of these reptiles 509 were tortoises, 28 monitor or other lizards, and 49 snakes. Nine ixodid tick species, of which seven belonged to the genus Amblyomma , and one argasid tick, Ornithodoros compactus were recovered. Seven of the ten tick species are parasites of reptiles. Amongst these seven species Amblyomma marmoreum was most prevalent and numerous on leopard tortoises, Geochelone pardalis ; Amblyomma nuttalli was present only on Bell's hinged tortoises, Kinixys belliana ; and most Amblyomma sylvaticum were collected from angulate tortoises, Chersina angulata. Amblyomma exornatum (formerly Aponomma exornatum ) was only recovered from monitor lizards, Varanus spp. ; most Amblyomma latum (formerly Aponomma latum ) were from snakes; and a single nymph of Amblyomma transversale (formerly Aponomma transversale ) was collected from a southern African python, Python natalensis . All 30 Namaqualand speckled padloper tortoises, Homopus signatus signatus , examined were infested with O. compactus . The seasonal occurrence of A. sylvaticum and the geographic distribution of this tick and of A. marmoreum, A. nuttalli, A. exornatum, A. latum and O. compactus are illustrated.

/pdf/parasites-of-domestic-and-wild-animals-in-south-africa-xlvii-1asxmpbz9o.pdf

Parasites of domestic and wild animals in South Africa. XLVII. Ticks of tortoises and other reptiles

A comparative phylogeographic study on two economically important African tick species, Amblyomma hebraeum and Hyalomma rufipes was performed to test the influence of host specificity and host movement on dispersion. Pairwise AMOVA analyses of 277 mtDNA COI sequences supported significant population differentiation among the majority of sampling sites. The geographic mitochondrial structure was not supported by nuclear ITS-2 sequencing, probably attributed to a recent divergence. The three-host generalist, A. hebraeum, showed less mtDNA geographic structure, and a lower level of genetic diversity, while the more host-specific H. rufipes displayed higher levels of population differentiation and two distinct mtDNA assemblages (one predominantly confined to South Africa/Namibia and the other to Mozambique and East Africa). A zone of overlap is present in southern Mozambique. A mechanistic climate model suggests that climate alone cannot be responsible for the disruption in female gene flow. Our findings furthermore suggest that female gene dispersal of ticks is more dependent on the presence of juvenile hosts in the environment than on the ability of adult hosts to disperse across the landscape. Documented interspecific competition between the juvenile stages of H. rufipes and H. truncatum is implicated as a contributing factor towards disrupting gene flow between the two southern African H. rufipes genetic assemblages.

/pdf/the-influence-of-interspecific-competition-and-host-27o10x28uw.pdf

The Influence of Interspecific Competition and Host Preference on the Phylogeography of Two African Ixodid Tick Species

The helminth parasites recovered from sheep, cattle, impala and blesbok during several surveys conducted in the Republic of South Africa are listed as definitive, occasional or accidental parasites of their respective hosts. Their distributions according to the various, c1imatic zones of the Republic are also listed.

Ivan Gerard Horak

Papers

Tick Vector Biology

Helminths and arthropods of black and white rhinoceroses in southern Africa.

Parasites of domestic and wild animals in South Africa. XLVII. Ticks of tortoises and other reptiles

The Influence of Interspecific Competition and Host Preference on the Phylogeography of Two African Ixodid Tick Species

Host specificity and the distribution of the helminth parasites of sheep, cattle, impala and blesbok according to climate.