Spatially different annual cycles but similar haemosporidian infections in distant populations of collared sand martins

Background Populations of long-distance migratory birds experience different environments and are consequently exposed to different parasites throughout their annual cycles. Though, specific whereabouts and accompanied host-parasite interactions remain unknown for most migratory passerines. Collared sand martins (Riparia riparia) breeding in the western Palaearctic spend the nonbreeding period in Africa, but it is not yet clear whether specific populations differ in overwintering locations and whether these also result in varying infections with vector-transmitted endoparasites. Results Geolocator tracking revealed that collared sand martins from northern-central and central-eastern Europe migrate to distant nonbreeding sites in West Africa and the Lake Chad basin in central Africa, respectively. While the ranges of these populations were clearly separated throughout the year, they consistently spent up to 60% of the annual cycle in Africa. Ambient light recorded by geolocators further indicated unsheltered roosting during the nonbreeding season in Africa compared to the breeding season in Europe. We found 5–26% prevalence of haemosporidian parasites in three breeding populations and one migratory passage population that was only sampled but not tracked. In total, we identified seven Plasmodium and nine Haemoproteus lineages (incl. two and seven new lineages, respectively), the latter presumably typical for swallows (Hirundinae) hosts. 99.5% of infections had a low intensity, typical for chronic infection stages, whereas three individuals (0.5%) showed high parasitaemia typical for acute infections during spring migration and breeding. Conclusions Our study shows that blood parasite infections are common in several western Palaearctic breeding populations of collared sand martins who spent the nonbreeding season in West Africa and the lake Chad region. Due to long residency at the nonbreeding grounds blood parasite transmissions may mainly occur at host population-specific residences sites in Europe and Africa; the latter being likely facilitated by unsheltered roosting and thus high vulnerability to hematophagous insects. The rare cases of high parasitaemia during spring migration and breeding further indicates either relapses of chronic infection or primary infections which occurred shortly before migration and during breeding.

Changes in Liver Function Enzymes in Plasmodium falciparum Infected Malaria Patients in Ajeromi General Hospital, Lagos, Nigeria

Objective: This study is to determine the changes in liver function enzymes in P. falciparum-infected patients in Ajeromi ifelodun area of Lagos, Nigeria by examining changes in some liver enzymes: Aspartate Transaminase (AST), Alanine Transaminase (ALT) and Alkaline phosphatase (ALP) obtained from newly diagnosed cases of malarial infection yet to be treated. Study Design: Seventy (70) human subjects comprising of 50 P. falciparum malarial infected and 20 non-infected (control) subjects between 10-60 years were selected for this study. Malaria positive subjects were divided into three groups based on the number of parasite per μl. Those that had parasitaemia below 10,000 parasites per μl were considered a mild infection, those that had parasitaemia above 10,000 parasites per μl were considered severe infections and those with parasitaemia below 1,000 parasites per μl were considered a low infection. RDT test and microscopy was carried out to ascertain the presence of P.falciparum. They were grouped based on age group, sex and level of parasitaemia. Materials and Methods: Blood samples were collected for the determination of P. falciparum, level of parasitaemia and liver function enzymes Aspartate Transaminase (AST), Alanine Transaminase (ALT) and Alkaline Phosphatase (ALP). P. falciparum was determined by Rapid Diagnostic Test (RDT) and microscopy. Results: There was a significant increase (P < 0.001) in the mean level of serum Aspartate Transaminase (AST), Alanine Transaminase (ALT) and a significant decrease in the mean level of alkaline phosphatase (ALP) in the P. falciparum-infected patients compared to the control subjects. AST level was found to be significantly higher (P<0.001) among age group (51- above) in the P. falciparum patients and significantly lower among age group (10-20) in the control subjects when compared to other age groups. ALT level was significantly higher (P < 0.001) among age group (51- above) in the P. falciparum patients and significantly lower among age group (41-50) in the control subjects when compared to other age groups. ALP level was significantly higher (P < 0.001) among age group (41-50) in the P. falciparum patients and significantly lower among age group (10-20) in the control subjects when compared to other age groups. AST and ALT were found to be significantly higher (P < 0.001) in the high parasitaemia group when compared to the low and moderate parasitaemia group and they were also significantly higher in the moderate parasitaemia group than in the low parasitaemia group.ALP was significantly higher (P < 0.001) in the moderate parasitaemia group when compared to the low and high parasitaemia group and they were only marginally lower in the high than in the low parasitaemia group. Conclusion: There was an elevated level of liver function enzymes in the P. falciparum patients than in the control subjects. This study shows that high parasitaemic patients are at greater risk of hepatic damage than the low parasitaemic group, hence early diagnosis and treatment of malaria are highly encouraged.

Plasmodium vivax cerebral malaria in an adult patient in Sudan

Background Plasmodium vivax infection is rising in sub-Saharan Africa, where Plasmodium falciparum is responsible for more than 90% of malaria cases. While P. vivax is identified as a major cause of severe and cerebral malaria in South east Asia, the Pacific and South America, most of the severe and cerebral cases in Africa were attributed to P. falciparum. Cases of severe malaria due to P. vivax are emerging in Africa. A few severe P. vivax cases were reported in Eastern Sudan and they were underestimated due to the lack of accurate diagnosis, low parasitaemia and seldom use of rapid diagnostic tests (RDTs). Case presentation A 60-year-old Sudanese male presented to the Al Kuwaiti hospital in the Sudan capital Khartoum. On admission, the patient was complaining of fever (measured temperature was 38 °C), sweating, chills, vomiting and confusion in the past 2 days prior to his admission. He rapidly deteriorated into a coma state within 48 h of the admission, with significant neck stiffness. He was admitted to the intensive care unit and was suspected of meningitis. Lumbar puncture was not performed since the patient was suffering from spinal cord disc. Brain CT scan was unremarkable. Several biochemical, haematological tests, and blood film for malaria were performed. The results of the laboratory tests were within the normal range except of mild elevation of the total white blood cell count and a significant decrease in the platelets count. Malaria parasites were seen in the blood film with high parasitaemia (quantified as 3 +++). The patient was diagnosed as P. vivax cerebral malaria based on the positive blood film and the amplification of P. vivax specific 499 bp amplicon using Plasmodium multi-species multiplex Polymerase Chain Reaction (PCR). The patient was treated with quinine 10 mg/kg body weight for 10 days followed by primaquine 15 mg/days PO for 2 weeks. The symptoms subsided within 48 h and the patients was cured and released from the hospital. Conclusions Plasmodium vivax is an emerging cause of cerebral malaria in adults in Sudan and should be considered in the differential diagnosis of cerebral malaria for proper management of patients.

Clinico-pathological studies of Plasmodium falciparum and Plasmodium vivax — malaria in India and Saudi Arabia

Malaria is one of the most devastating diseases of tropical countries with clinical manifestations such as anaemia, splenomegaly, thrombocytopenia, hepatomegaly and acute renal failures. In this study, cases of thrombocytopenia and haemoglobinemia were more prominent in subjects infected with Plasmodium falciparum (Welch, 1897) than those with Plasmodium vivax (Grassi et Feletti, 1890). However, anaemia, jaundice, convulsions and acute renal failure were significantly high (3–4 times) in subjects infected with P. falciparum than those infected with P. vivax. The incidence of splenomegaly and neurological sequelae were 2 and 6 times higher in P. falciparum infections compared to the infections of P. vivax. Both in P. vivax and P. falciparum malaria, the cases of splenomegaly, jaundice and neurological sequelae were almost double in children (<10 years) compared to older patients. The liver enzymes were generally in normal range in cases of low and mild infections. However, the AST, ALT, ALP activities and serum bilirubin, creatinine, and the urea content were increased in P. falciparum and P. vivax malaria patients having high parasitaemia, confirming liver dysfunction and renal failures in few cases of severe malaria both in India and Saudi Arabia.

Primary peak and chronic malaria infection levels are correlated in experimentally infected great reed warblers

SUMMARYMalaria parasites often manage to maintain an infection for several months or years in their vertebrate hosts. In humans, rodents and birds, most of the fitness costs associated with malaria infections are in the short initial primary (high parasitaemia) phase of the infection, whereas the chronic phase (low parasitaemia) is more benign to the host. In wild birds, malaria parasites have mainly been studied during the chronic phase of the infection. This is because the initial primary phase of infection is short in duration and infected birds with severe disease symptoms tend to hide in sheltered places and are thus rarely caught and sampled. We therefore wanted to investigate the relationship between the parasitaemia during the primary and chronic phases of the infection using an experimental infection approach. We found a significant positive correlation between parasitaemia in the primary peak and the subsequent chronic phase of infection when we experimentally infected great reed warblers (Acrocephalus arundinaceus) withPlasmodium ashfordi. The reason for this association remains to be understood, but might arise from individual variation in exoerythrocytic parasite reservoirs in hosts, parasite antigenic diversity and/or host genetics. Our results suggest that the chronic phase parasitaemia can be used to qualitatively infer the parasitaemia of the preceding and more severe primary phase, which is a very important finding for studies of avian malaria in wild populations.

Comparison of the transmissibility ofTrypanosoma congolensestrains, isolated in a trypanosomiasis endemic area of eastern Zambia, byGlossina morsitans morsitans

Transmission experiments were conducted to compare the transmissibility of genetically differentTrypanosoma congolense(Savannah subgroup) strains isolated from cattle in a trypanosomiasis endemic area of eastern Zambia. A total of 17 strains were compared. Three strains were extremely virulent with a short pre-patent period, high parasitaemia and a short median survival time (between 5 and 9 days) in mice. The remainder of the strains belonged to the moderate (6 strains) or low (8 strains) virulence categories with median survival times between 10 and 30 days and >30 days, respectively. Batches of 40 teneralGlossina morsitans morsitans(Diptera: Glossinidae) were offered a single bloodmeal on mice infected with one of those strains. Flies were dissected to determine their infection status 21 days later. The proportion of flies with procyclic and metacyclic infections differed significantly between trypanosome strains and were significantly higher in flies infected with extremely virulent strains (P=0·033 andP=0·016 for the differences in the procyclic infection rate of strains with moderate and low virulence, respectively andP=0·005 andP=0·019 for the differences in the metacyclic infection rate of strains with moderate and low virulence, respectively). On the other hand, moderately virulent strains had, in general, higher procyclic and metacyclic infection rates compared to low virulent strains. But the differences were not significant (P>0·05). The outcome of those experiments shows clear differences in transmissibility of trypanosome strains associated with their virulence. This observation confirms the theory for the evolution and maintenance of virulence in a parasite population and may explain the persistence of virulent trypanosome strains in a susceptible host population.

Survey of canine babesiosis in South Africa

A questionnaire, designed to obtain qualitative information on a number of variables concerning canine babesiosis (biliary fever) in South Africa, was sent to 510 veterinary practices in late 1993. Of the 157 practices that responded, all were presented with cases of babesiosis and most were situated in Gauteng, the Western Cape and KwaZulu-Natal. Apart from the Western Cape, a winter-rainfall region, the prevalence of babesiosis cases in dogs was highest in summer. Most of the respondent practices treated between 1000 and 5000 sick dogs that included 100 to 500 babesiosis cases each year. Respondents identified cerebral babesiosis, enterorrhagia, 'red' or haemoconcentrated babesiosis, acute renal failure and pulmonary babesiosis or 'shock lung', amongst others, as the most prevalent forms of complicated ('atypical') babesiosis. Diminazene, imidocarb and trypan blue were the most popular antibabesials. Trypan blue was most often used in shocked patients, whereas diminazene and imidocarb were preferred when there was a high parasitaemia in the absence of shock. At least 19 antibabesial treatment regimens were used in practices. These comprised the use of single doses of antibabesial drugs; split doses with repeat injections, and combined drug variations, some of which are undesirable due to possible sterilisation of Babesia infection or potential toxicity. Side-effects were most commonly associated with imidocarb use. Ninety-six percent of respondents used supportive treatment (e.g. corticosteroids, vitamins and 'liver support') in all cases of babesiosis. The use of blood transfusion as supportive treatment varied according to practice and severity of the case. Most practices never cross-matched blood to be transfused, and transfusion reactions were rare. Diminazene was most frequently incriminated in cases where drug 'resistance' or relapses occurred. Cerebral and 'red' cases resulted in high mortality. Treatment of babesiosis costs the dog-owning public in South Africa more than R20 million each year. Information on the distribution and possible complicating role of Ehrlichia canis was obtained. Development of a vaccine was the first research priority identified.