Visceral pentastomiasis in humans is caused by the larval stages (nymphs) of the arthropod-related tongue worms Linguatula serrata, Armillifer armillatus, A. moniliformis, A. grandis, and Porocephalus crotali. The majority of cases has been reported from Africa, Malaysia, and the Middle East, where visceral pentastomiasis may be an incidental finding in autopsies, and less often from China and Latin America. In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis. Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations. This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.
Sarcocystosis, an unusual parasitic zoonotic disease, is caused by coccidian/ apicomplexan protozoa in humans and animals. The parasites usually develop in a heteroxenous predator-prey life-cycle involving final (carnivore) and intermediate (omnivore/herbivore) hosts. Besides the intestinal, non-invasive form of the disease in which humans and animals are the definitive hosts for certain Sarcocystis spp., the invasive form has come to recent attention. In the latter, humans and animals serve as intermediate host harbouring sarcocysts in their muscle tissue. Already in 1991 sarcocystosis was seen as a potential emerging food borne zoonosis in Malaysia, and in 2011 and 2012 the largest cluster of symptomatic human muscular sarcocystosis world-wide was reported from Tioman Island, Pahang state. In this review, we focus on invasive sarcocystosis in humans and animals in Malaysia, review the recorded cases and epidemiology, and present hypotheses.
We report a case of visceral pentastomiasis caused by Armillifer moniliformis in a 70-year-old aboriginal farmer from rural Malaysian Borneo. The patient complained of upper abdominal pain, jaundice, and loss of weight. Radiological investigations and subsequent histopathological examination revealed an adenocarcinoma of the pancreas with an adjacent liver nodule containing a nymph of A. moniliformis. This report constitutes the first documented human pentastomid infection in the whole of Malaysia after nearly 40 years, and it is the third description from Malaysian Borneo. Cases of human and animal pentastomiasis in Malaysia are discussed.
The prevalence of sarcocystosis in cattle and water buffaloes from peninsular Malaysia was investigated in abattoirs in Selangor state, February, 2011, to March, 2012. Fresh muscle samples were collected from the tongue, heart, oesophagus, diaphragm and skeletal muscles of 102 cattle and 18 water buffaloes. Each sample was initially screened by light microscopy and then fixed for further histopathological analysis. Out of 120 animals examined, 49 (40.8%) harboured the microscopic type of Sarcocystis spp. The positivity rate for cattle was 36.2% and for water buffaloes 66.7%. In cattle, the organs highly infected were the skeletal muscles and diaphragm (27% each), followed by tongue and esophagus (24.3% each), and the heart (8%). In water buffaloes, the heart was most often infected (66.7%), followed by the oesophagus (50%) and skeletal muscle (33.3%); no sarcocysts were detected in the tongue and diaphragm. The shape of the sarcocyst was fusiform to oval with a mean cyst size of 151.66 x 75.83 μm and wall thickness of 2.47 μm in cattle, and 114 x 50.81 μm cyst size and the wall thickness of 1.11 μm in water buffaloes, consistent with Sarcocystis cruzi and Sarcocystis levinei, respectively. Remaining tissue from cattle was subjected to parasite specific 18S rRNA gene PCR and Sarcocystis cruzi was confirmed, at least exemplarily. The peripheral metrocytes and the banana-shaped bradyzoites (15.23 x 2.2 μm in cattle and 11.49 x 2.45 μm in water buffalo hosts) were easily recognized. In conclusion, a high positivity rate was found in Malaysian meat-producing animals with possible implications for meat consumption and human health.
Ticks are blood-feeding ectoparasites and major vectors of pathogens that cause infectious diseases in humans and animals worldwide including mammals, birds and reptiles. Despite the growing scientific effort in the 20th century, there is still limited information on ticks and tick-borne pathogens in Southeast Asia, especially concerning medical, veterinary, socioeconomic and agricultural aspects in the island nations. This review provides an overview of the current state of knowledge of ticks and their pathogens in the island nations of Southeast Asia and peninsular Malaysia. We aim to stimulate further research studies on ticks and tick-borne pathogens of human and veterinary importance in this geographical region.
Soft ticks (Acari: Argasidae) are the second major family of the blood feeding metastriates and vectors of a number of viral and bacterial pathogens for both humans and animals. Despite the growing effort on tick surveillance and studies worldwide, there is still limited information on the soft tick distribution in the island nations of Southeast Asia, especially species that are medically and veterinarily important. With the aim to provide an overview of the current status of knowledge on soft tick distribution in the island nations of Southeast Asia (Malaysia, Singapore, Brunei, Indonesia, the Philippines and Timor-Leste), this article reviews the species of soft ticks (Acari: Argasidae) and their associated hosts and pathogens, with the addition of a pictorial summary and list of tick species discovered in this region. The most prevalent soft tick genus is Carios, and the host species most associated with findings of soft ticks in this region are bats, particularly of the Pteropodidae and Vespertilionidae families. Furthermore, the only known pathogen originating from soft ticks in the island nations of Southeast Asia was the Keterah virus, which was isolated from Argas pusillus tick in Malaysia.
In May 2014, six patients presented in Germany with a Sarcocystis-associated febrile myositis syndrome after returning from Tioman Island, Malaysia. During two earlier waves of infections, in 2011 and 2012, about 100 travellers returning to various European countries from the island were affected. While the first two waves were associated with travel to Tioman Island mostly during the summer months, this current series of infections is associated with travel in early spring, possibly indicating an upcoming new epidemic.
Studies of ticks in Malaysia from past articles were reviewed, resulting in a list of 47 species belonging to seven genera (Argas, Ornithodoros, Amblyomma, Dermacentor, Haemaphysalis, Ixodes, and Rhipicephalus). The most prevalent genus in Malaysia is Haemaphysalis (20 species), followed by Amblyomma (eight species) and Dermacentor (seven species). Out of 47 species, only 28 have bitten humans, mostly belonging to Haemaphysalis. The most researched tick-borne pathogens in Malaysia are Rickettsia and Anaplasma, and most research was focused on the tropical-lineage brown dog ticks, R. sanguineus sensu lato, and the cattle ticks, Haemaphysalis bispinosa and Rhipicephalus microplus. 18 species were excluded from the list due to lack of definite records or dubious findings: Ornithodoros mimon, O. turicata, Amblyomma breviscutatum, A. clypeolatum, A. integrum, A. maculatum, Dermacentor marginatum, D. taiwanensis, Haemaphysalis birmaniae, H. flava, H. humerosa, H. longicornis, H. punctata, H. sulcata, Ixodes holocyclus, Rhipicephalus appendiculatus, R. annulatus and R. bursa. This paper presents the first complete and updated list for Dermacentor and Ixodes tick species in Malaysia since Kohls (1957).
Literature records of chewing lice (Phthiraptera) from mammals in Malaysia were checked and reviewed, resulting in a list of 13 confirmed species belonging to eight genera (Bovicola, Felicola, Gliricola, Gyropus, Haematomyzus, Heterodoxus, Lorisicola, Trichodectes) from four families (Boopiidae, Gyropidae, Haematomyzidae, Trichodectidae) in three suborders (Amblycera, Ischnocera, Rhynchophthirina). We present a checklist of those 13 chewing lice recorded from Peninsular Malaysia and Malaysian Borneo, including hosts, localities, and literature references. An additional 12 species are listed and discussed as possibly occurring in this country. A host-louse list is also given.
Literature records of sucking lice (Phthiraptera: Anoplura) from Malaysia were checked and reviewed, resulting in a list of 34 established species belonging to 11 genera (Ancistroplax, Atopophthirus, Enderleinellus, Haematopinus, Hamophthirius, Hoplopleura, Linognathus, Neohaematopinus, Pedicinus, Polyplax and Sathrax). Furthermore, three local and six cosmopolitan louse species are regarded as dubious in Malaysia, due to misidentifications or lack of locality records. Also, pathogens known to be associated with the sucking lice are listed. The alarming conservation status of some Malaysian mammalian host species and their sucking lice warrant more research and imminent action to preserve the biodiversity of the country. This paper presents the first complete checklist of anopluran lice from both Peninsular Malaysia and Malaysian Borneo, including localities, literature references and a host-louse list.
We report the presence of a male Haemaphysalis semermis collected from the domestic cat, Felis catus in an aboriginal village located in Pahang, Malaysia. This paper constitutes a new host record of this tick species, and also the first documentation of the infestation of companion animals other than domestic dogs (Canis lupus) by H. semermis in Malaysia. Additionally, we have included an updated host index of the tick species in Southeast Asia.
We report two new records of chewing lice from avian pets in Peninsular Malaysia: Colpocephalum apivorus Tendeiro, 1958 from an Oriental honey buzzard (Pernis ptilorhynchus (Temminck, 1821)), and Myrsidea splendenticola Klockenhoff, 1973 from an albino house crow (Corvus splendens Vieillot, 1817). The scarcity of louse records from avian pets and wild birds, and the lack of louse research in Malaysia are discussed.
This paper describes a new tick-host record of Haemaphysalis wellingtoni from the helmeted guineafowl (Numida meleagris) in Peninsular Malaysia. This record is also the first report of a tick infestation from N. meleagris in Asia. A checklist of the tick-guineafowl associations has been designed, resulting in 32 tick species including H. wellingtoni recorded as infesting N. meleagris worldwide. A list of pathogens harboured or transmitted by H. wellingtoni is provided. The status of H. wellingtoni as a true parasite of N. meleagris, and the health threat posed to the guineafowls are discussed in this paper.
Since 2011, about 100 travellers to the island of Tioman, Malaysia, have been diagnosed worldwide with suspected muscular sarcocystosis, a previously only sporadically observed parasitic disease. Source of infection and therapy remain unclear. Final diagnosis requires microscopic identification of cysts in muscle biopsies. The study objective was a systematic description of characteristic symptoms, laboratory investigations and treatment response.
Rickettsioses of the typhus group (TG) and spotted fever group (SFG) are emerging bacterial infections worldwide, especially in the tropics. Only a few studies on these pathogens and their respective clinical diseases have been conducted in Malaysia. Here, we performed a seroprevalence study among 544 healthy, afebrile indigenous people (Orang Asli) from peninsular Malaysia for TG and SFG rickettsioses in nine rural and peri-urban settlements. The study population encompassed children, adolescents, and adults. The overall seroprevalence of rickettsiosis in the Orang Asli was 48.5%, with 27.9% seroprevalence against TG rickettsiae and 20.6% seroprevalence against SFG rickettsiae. In 7.9% of the study participants, antibodies against both rickettsial groups were found. The highest seropositivity rates against TG and SRG rickettsiae were detected in young children and adults. Overall, there were no gender differences. Seroprevalences were similar among inhabitants of different settlements, except for two localities. More studies are needed to shed more light on the ecology and risk factors for TG and SFG rickettsioses in Malaysia.
Streptococcal toxic shock syndrome is a serious health problem in developed and developing countries. We here report a case of severe protracted disease after a minor skin infection in a young traveler returning from West Malaysia which was caused by an unusual emm-type strain harboring speG and smeZ superantigen genes.